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Adding a Node to an Oracle RAC 10g Release 2 Cluster on Linux - (CentOS 4.5 / iSCSI)
by Jeff Hunter, Sr. Database Administrator
Contents
Overview
This document is an extension to my article
"Building an Inexpensive Oracle RAC 10g Release 2 on Linux - (CentOS 4.5 / iSCSI)".
Contained in this new article are the steps required to add a single node
to an already running and configured
two-node Oracle RAC 10g Release 2 environment on the
CentOS 32-bit (x86) platform. Although this article was written and
tested on CentOS 4.5 Linux, it should work unchanged with
Red Hat Enterprise Linux 4 Update 5.
This article assumes the following:
Note: The current two-node Oracle RAC
environment has been upgraded from its base release (10.2.0.1.0) to
version 10.2.0.3.0 by applying the 5337014 patchset (p5337014_10203_LINUX.zip).
The patchset was applied to Oracle Clusterware and the Oracle Database
software. I also applied the one-off patchset - "BUNDLE Patch for Base Bug 6000740"
(MLR7 ON TOP OF 10.2.0.3) to the Oracle Clusterware and Oracle
Database software. The procedures for installing both patchsets are
not included in any of the parent article(s).
The following is a conceptual look at what the environment will look like
after adding the third Oracle RAC node (linux3) to the cluster. Click on the
graphic below to enlarge the image:
Figure 1: Adding linux3 to the current Oracle RAC 10g Release 2 Environment
- Intel(R) Pentium(R) 4 Processor at 2.80GHz
Each Linux server for Oracle RAC should contain two NIC adapters.
The Dell Dimension includes an integrated 10/100 Ethernet adapter
that will be used to connect to the public network. The second NIC adapter
will be used for the private network (RAC interconnect and
Openfiler networked storage). Select the appropriate NIC adapter
that is compatible with the maximum data transmission speed of the
network switch to be used for the private network.
For the purpose of this article, I used a Gigabit Ethernet switch (and 1Gb Ethernet cards)
for the private network.
Used for RAC interconnect to linux1, linux2 and Openfiler networked storage.
Gigabit Ethernet
Install the Linux Operating System
After procuring the required hardware, it is time to start the configuration
process. The first task we need to perform is to install the
Linux operating system. As already mentioned, this article will use CentOS 4.5.
Although I have used Red Hat Fedora in the past, I wanted to switch
to a Linux environment that would guarantee all of the functionality
contained with Oracle. This is where CentOS comes in.
The CentOS project takes the Red Hat Enterprise Linux 4 source RPMs and compiles
them into a free clone of the Red Hat Enterprise Server 4 product. This provides
a free and stable version of the Red Hat Enterprise Linux 4 (AS/ES) operating environment that
I can now use for
testing different Oracle configurations. I have moved away from Fedora as I need a
stable environment that is not only
free, but as close to the actual Oracle supported operating system as possible.
While CentOS is not the only project performing the same functionality, I
tend to stick with it as it is stable and reacts fast with regards to updates by Red Hat.
After downloading and burning the CentOS images (ISO files) to CD,
insert CentOS Disk #1 into the new Oracle RAC server (linux3 in this example), power it on,
and answer the installation screen prompts as noted below.
Boot Screen
If there were
a previous installation of Linux on this machine, the next screen
will ask if you want to "remove" or "keep" old partitions. Select the option
to [Remove all partitions on this system]. Also, ensure that the
[hda] drive is selected for this installation. I also keep the
checkbox [Review (and modify if needed) the partitions created] selected.
Click [Next] to continue.
You will then be prompted with a dialog window asking if you really
want to remove all partitions. Click [Yes] to acknowledge this warning.
The main concern during
the partitioning phase is to ensure enough swap space is allocated as
required by Oracle (which is a multiple of the available RAM).
The following is Oracle's requirement for swap space:
For the purpose of this install, I will accept
all automatically preferred sizes. (Including 2GB for swap since I have
2GB of RAM installed.)
If for any reason, the automatic layout does not
configure an adequate amount of swap space, you can easily change that from this screen.
To increase the size of the swap partition, [Edit] the volume group VolGroup00.
This will bring up the "Edit LVM Volume Group: VolGroup00" dialog.
First, [Edit] and decrease the size of the root file system (/) by the amount you
want to add to the swap partition. For example, to add another 512MB to swap, you would
decrease the size of the root file system by 512MB (i.e. 36,032MB - 512MB = 35,520MB).
Now add the space you decreased from the root file system (512MB) to the swap
partition. When completed, click [OK] on the "Edit LVM Volume Group: VolGroup00"
dialog.
Once you are satisfied with the disk layout, click [Next] to continue.
First, make sure that each of the network devices are checked
to [Active on boot]. The installer may choose
to not activate eth1 by default.
Second, [Edit] both eth0 and eth1 as follows. You may choose
to use different IP addresses for both eth0 and eth1 and that
is OK. Configure eth1 (the interconnect and storage network) on
a different subnet than eth0 (the public network):
eth0:
eth1:
Continue by setting your hostname manually. I used
"linux3" for this new Oracle RAC node.
Finish this dialog off by supplying your gateway and
DNS servers.
You will be prompted
with a warning dialog about not setting the firewall.
If this occurs, simply hit [Proceed] to continue.
Please note that the installation of Oracle does not require
all Linux packages to be installed. My decision to install
all packages was for the sake of brevity.
Please see section
"Pre-Installation Tasks for Oracle10g Release 2"
for a more detailed
look at the critical packages required for a successful
Oracle installation.
Also note that with some RHEL 4 distributions, you will not get the "Package Group Selection"
screen by default. There, you are asked to simply "Install default
software packages" or "Customize software packages to be installed".
Select the option to "Customize software packages to be installed"
and click [Next] to continue. This will then bring up the
"Package Group Selection" screen. Now, scroll down to the bottom of this screen and select
[Everything] under the "Miscellaneous" section. Click
[Next] to continue.
Note that with CentOS 4.5, the installer would ask to switch
to Disk #2, Disk #3, Disk #4, Disk #1, and then back to Disk #4.
When the system boots into Linux for the first time, it will prompt
you with another Welcome screen. The following wizard allows you to
configure the date and time, add any additional users, test the
sound card, and to install any additional CDs. The only screen I care
about is the time and date (and if you are using CentOS 4.x, the
monitor/display settings). As for the others, simply run through
them as there is nothing additional that needs to be installed (at this point
anyways!). If everything was successful, you should now be presented with the
login screen.
During the Linux O/S install we already configured the IP address and
host name for the new Oracle RAC node.
We now need to configure
the /etc/hosts file as well as adjusting several of the
network settings for the interconnect.
All nodes in the RAC cluster should have one static IP address for the public network
and one static IP address for the private cluster interconnect. The
private interconnect should only be used by Oracle to transfer
Cluster Manager and Cache Fusion related data along with data for the
network storage server (Openfiler). Although it is possible
to use the public network for the interconnect, this not recommended as
it may cause degraded database performance (reducing the amount of bandwidth
for Cache Fusion and Cluster Manager traffic). For a production RAC implementation,
the interconnect should be at least gigabit (or more) and only be used by Oracle
as well as having the network storage server (Openfiler) on a separate gigabit network.
The easiest way to configure network settings in Red Hat Linux is with the program
Network Configuration. This application can be started from the command-line
as the "root" user account as follows:
Using the Network Configuration application, we will need to configure
both NIC devices as well as the
Please note that for the purpose of this example configuration
the
Our example configuration will use the following settings for all nodes:
Oracle Database 10g CRS Release 10.2.0.1.0 Production Copyright 1996, 2005 Oracle. All rights reserved.
Oracle strongly suggests to adjust the default and maximum send buffer size
(SO_SNDBUF socket option) to 256 KB, and the default and maximum receive
buffer size (SO_RCVBUF socket option) to 256 KB.
The receive buffers are used by TCP and UDP to hold received data until it is read by
the application. The receive buffer cannot overflow because the peer is not allowed to
send data beyond the buffer size window. This means that datagrams will be discarded if
they don't fit in the socket receive buffer. This could cause the sender to overwhelm
the receiver.
The default and maximum window size can be changed without a reboot.
Add the following entries to the /etc/sysctl.conf file
on the new Oracle RAC node:
If UDP ICMP is blocked or rejected by the firewall, the Oracle Clusterware software will crash after several minutes
of running. When the Oracle Clusterware process fails, you will have something similar to the following
in the <machine_name>_evmocr.log file:
Configure Network Security on the Openfiler Storage Server
With the network now setup, the next step is to configure
network access in Openfiler so that the new Oracle RAC node
(linux3) has permissions to the shared iSCSI volumes
used in the current Oracle RAC 10g environment. For
the purpose of this example, all iSCSI traffic will use the
private network interface eth1 which in this article
is on the 192.168.2.0 network.
Openfiler administration is performed using the Openfiler Storage Control Center —
a browser based tool over an https connection on port 446. For example:
The first page the administrator sees is the
[Accounts] / [Authentication] screen. Configuring user accounts
and groups is not necessary for this article and will
therefore not be discussed.
To verify the iSCSI services are running, use the Openfiler Storage Control Center and
navigate to [Services] / [Enable/Disable]:
Another method is to SSH into the Openfiler server and
verify the iscsi-target service is running:
Again, this task can be completed using the Openfiler Storage Control Center
by navigating to [General] / [Local Networks]. The Local Networks screen allows
an administrator to setup networks and/or hosts that will be allowed to
access resources exported by the Openfiler appliance. For the purpose of this
article, we will want to add the new Oracle RAC node individually rather than allowing
the entire 192.168.2.0 network have access to Openfiler resources.
When entering the new Oracle RAC node, note that the 'Name' field
is just a logical name used for reference only. As a convention when entering
nodes, I simply use the node name defined for that IP address.
Next, when entering the actual node in the 'Network/Host' field, always use it's
IP address even though its host name may already be defined in your /etc/hosts
file or DNS. Lastly, when entering actual hosts in our Class C network, use
a subnet mask of 255.255.255.255.
It is important to remember that you will be entering the IP address
of the private network (eth1) for the new Oracle RAC node.
The following image shows the results of adding the new Oracle RAC node linux3
to the local network configuration:
To view the available iSCSI volumes from within the Openfiler Storage Control Center,
navigate to [Volumes] / [List of Existing Volumes]. There we will see all five
logical volumes within the volume group rac1:
From the Openfiler Storage Control Center, navigate to
[Volumes] / [List of Existing Volumes]. This will present the screen shown in the
previous section. For each of the five logical volumes, click on the 'Edit' link (under
the Properties column). This will bring up the 'Edit properties' screen for that
volume. Scroll to the bottom of this screen; change the access for host linux3-priv from
'Deny' to 'Allow' and click the 'Update' button. Perform this task for all five logical volumes.
An iSCSI client can be any system (Linux, Unix, MS Windows, Apple Mac, etc.) for which iSCSI
support (a driver) is available. In our case, the clients are the three Oracle RAC nodes,
(linux1, linux2, and linux3), running Red Hat 4.
In this section we will be configuring the iSCSI initiator on the new Oracle RAC node linux3.
This involves configuring the /etc/iscsi.conf file on the new Oracle
RAC node with the name of the network storage server (openfiler1) so it can
discover the current iSCSI volumes.
Use the following command to install the iscsi-initiator-utils RPM package if not present:
After verifying that the iscsi-initiator-utils RPM is installed, the only
configuration step required on the new Oracle RAC node (iSCSI client) is to specify the
network storage server (iSCSI server) in the /etc/iscsi.conf file.
Edit the /etc/iscsi.conf file and include an entry for
DiscoveryAddress which specifies the hostname of the Openfiler network storage server.
In our case that was:
In this section, we simply want to verify that the new Oracle RAC node
was able to successfully discover the five logical iSCSI volumes
on the Openfiler server.
When the Openfiler server publishes available iSCSI targets,
configured clients get the message that new iSCSI disks are now available.
This happens when the iscsi-target service gets started/restarted on the Openfiler server
or when the iSCSI initiator service is started/restarted on the client.
We would see something like this in the client's /var/log/messages file:
Another method not
only checks for the existence of the iSCSI volumes, but also displays how the local SCSI device
names map to iSCSI targets' host IDs and LUNs. Use the following
script which was provided by
Martin Jones
to display these mappings:
Example run:
Create "oracle" User and Directories
I will be using the Oracle Cluster File System, Release 2 (OCFS2) to store the files required to be shared
for the Oracle Clusterware software.
When using OCFS2, the UID of the UNIX user "oracle" and GID of the UNIX group "oinstall" must be the same
on all of the Oracle RAC nodes in the cluster. If either the UID or GID are different, the files on the OCFS2 file system
will show up as "unowned" or may even be owned by a different user. For this article and its parent
article, I will use 501 for the "oracle" UID and 501 for the "oinstall" GID.
Note that members of the UNIX group oinstall are considered the "owners" of
the Oracle software.
Members of the dba group can administer Oracle databases, for example starting up and shutting
down databases. In this article, we are creating the oracle user account to have both
responsibilities!
The following assumes that the directories are being created in the root
file system. Please note that this is being done for the sake of
simplicity and is not recommended as a general practice. Normally, these
directories would be created on a separate file system.
After the directory is created, you must then specify the correct
owner, group, and permissions for it. Perform the following on the new Oracle
RAC node:
At the end of this procedure, you will have the following:
As noted in the previous section, the following assumes that the directories are being
created in the root file system. This is being done for the sake of simplicity
and is not recommended as a general practice. Normally, these directories would
be created on a separate file system.
After the directory is created, you must then specify the correct
owner, group, and permissions for it. Perform the following on the new Oracle
RAC node:
At the end of this procedure, you will have the following:
Perform the following on the new Oracle RAC node:
For this example, I used:
Login to the new Oracle RAC node as the oracle user account:
Configure the Linux Server for Oracle
The kernel parameters and shell limits discussed in this section will need to be defined on the new Oracle RAC node
every time the machine is booted. This section will not go into great depth in explaining the purpose
of those kernel parameters that are required by Oracle (These parameters are described in detail
in the
parent
to this article). Provided in this section, however, are instructions on how to set
all required kernel parameters for Oracle and how to have them enabled when the node boots.
Further instructions for configuring kernel parameters in
a startup script (/etc/sysctl.conf) is included in the section
"All Startup Commands for New Oracle RAC Node".
As root, make a file that will act as additional swap space, let's say about 500MB:
Now we should change the file permissions:
Finally we format the "partition" as swap and add it to the swap space:
On the new Oracle RAC node, verify that the kernel parameters described in this section are
set to values greater than or equal to the recommended values. Also note that when
setting the four semaphore values that all four values need to be entered on one line.
To make these changes, run the following as root:
We could reboot at this point to ensure all of these parameters are set in the
kernel or we could simply "run" the /etc/sysctl.conf file by running the
following command as root on the new Oracle RAC node:
Please note that although this would seem like a severe error from the OUI, it can
safely be disregarded as a warning. The "tar" command DOES actually
extract the files; however, when you perform a listing of the files (using ls -l) on the remote node
(the new Oracle RAC node),
they will be missing the time field until the time on the remote server is greater than the
timestamp of the file.
Before attempting to add the new node, ensure that all nodes in the cluster
are set as closely as possible to the same date and time. Oracle strongly recommends using
the Network Time Protocol feature of most operating systems for this purpose,
with all nodes using the same reference Network Time Protocol server.
Accessing a Network Time Protocol server, however, may not always be an option.
In this case, when manually setting the date and time for the nodes in the
cluster, ensure that the date and time of the node you are performing the software
installations from (linux1) is less than the new node being added to the cluster (linux3).
I generally use a 20 second difference as shown in the following example:
Show the date and time from linux1:
Setting the date and time on the new Oracle RAC node linux3:
The RAC configuration described in this article does not make use
of a Network Time Protocol server.
Configure the "hangcheck-timer" Kernel Module
Oracle 9.0.1 and 9.2.0.1 used a userspace watchdog daemon called
watchdogd to monitor the health of the cluster and to
restart a RAC node in case of a failure. Starting with Oracle 9.2.0.2
(and still available in Oracle10g Release 2), the
watchdog daemon has been deprecated by a Linux kernel module named
hangcheck-timer which addresses availability and reliability
problems much better. The hang-check timer is loaded into the
Linux kernel and checks if the system hangs. It will set a timer and check the
timer after a certain amount of time. There is a configurable threshold to
hang-check that, if exceeded will reboot the machine. Although
the hangcheck-timer module is not required for Oracle Clusterware (Cluster Manager)
operation, it is highly recommended by Oracle.
Much more information about the
hangcheck-timer project
can be found
here.
These values need to be available after each reboot of the Linux server. To do this, make
an entry with the correct values to the /etc/modprobe.conf file as follows:
It is only out of pure habit that I continue to include a modprobe
of the hangcheck-timer kernel module in the /etc/rc.local file. Someday I will get
over it, but realize that it does not hurt to include a modprobe of
the hangcheck-timer kernel module during startup.
So to keep myself sane and able to
sleep at night, I always configure the loading of the hangcheck-timer kernel module on
each startup as follows:
Now, to test the hangcheck-timer kernel module to verify it is picking up the
correct parameters we defined in the /etc/modprobe.conf file, use the modprobe
command. Although you could load
the hangcheck-timer kernel module by passing it the appropriate parameters
(e.g. insmod hangcheck-timer hangcheck_tick=30 hangcheck_margin=180),
we want to verify that it is picking up the options we set in the
/etc/modprobe.conf file.
To manually load the hangcheck-timer kernel module and verify it is using the
correct values defined in the /etc/modprobe.conf file, run the following command:
Configure RAC Nodes for Remote Access using SSH
As was the case when configuring the existing two-node cluster,
this article assumes the Oracle software installation to the new Oracle RAC node
will be performed from linux1. This section provides the
methods required for configuring SSH1, an RSA key, and user equivalence for
the new Oracle RAC node.
Use the following steps to create the RSA key pair from the new Oracle RAC node (linux3);
This command will write the public key to the ~/.ssh/id_rsa.pub
file and the private key to the ~/.ssh/id_rsa file.
Note that you should never distribute the private key to anyone!
Complete the following steps on linux1 to
update and then distribute the authorized key file to all nodes
in the Oracle RAC cluster.
Again, this task will be performed from linux1.
User equivalence will need to be enabled on any new terminal shell session
on linux1
before attempting to run the addNode.sh script. If you log out and log back in to the
node you will be performing the Oracle installation from, you must
enable user equivalence for the terminal shell session as this is not
done by default.
To enable user equivalence for the current terminal shell session, perform
the following steps:
As your organization grows so too does your need for more application and database resources
to support the company's IT systems. Oracle RAC 10g provides a scalable framework which allows DBA's
to effortlessly extend the database tier to support this increased demand. As the number of
users and transactions increase, additional Oracle instances can be added to the Oracle database
cluster to distribute the extra load.
The reader has already built and configured a two-node
Oracle RAC 10g Release 2 environment using the article
"Building an Inexpensive Oracle RAC 10g Release 2 on Linux - (CentOS 4.5 / iSCSI)".
The article provides comprehensive instructions for building a
two-node RAC cluster, each with a single processor
running CentOS 4.5, Oracle RAC 10g Release 2,
OCFS2, and ASMLib 2.0. The current two-node RAC environment
actually consists of three machines — two named
linux1 and linux2 which each run
an Oracle10g instance and a third node to
run the network storage server named openfiler1.
To maintain the current naming convention, the new Oracle RAC node to be added to the existing cluster will
be named linux3 (running a new instance named orcl3) making it a three-node cluster.
The new Oracle RAC node should have the same operating system version and installed patches
as the current two-node cluster.
Each node in the existing Oracle RAC cluster has a copy of the Oracle Clusterware and Oracle Database software
installed on their local disks. The current two-node Oracle RAC environment does not
use shared Oracle homes for the Clusterware or Database software.
The software owner for the Oracle Clusterware and Oracle Database installs will be
"oracle". It is important that the UID and GID of the oracle user
account be identical to that of the existing RAC nodes. For the purpose of this example,
the oracle user account will be defined as follows:
[oracle@linux1 ~]$ id oracle
uid=501(oracle) gid=501(oinstall) groups=501(oinstall),502(dba)
The existing Oracle RAC 10
Automatic Storage Management (ASM) is being used as the file system and volume manager
for all Oracle physical database files (data, online redo logs, control files, archived redo logs)
and a Flash Recovery Area. In addition to ASM, we will also be configuring ASMLib
on the new Oracle RAC node.
To add instances to an existing RAC database, Oracle Corporation recommends
using the Oracle cloning procedures which is described
in the Oracle Universal Installer and OPatch User's Guide. This article, however, uses manual procedures
to add nodes and instances to the existing Oracle RAC cluster. The manual procedures
method described in this article involve extending the RAC database by first
extending the Oracle Clusterware home to the new Oracle RAC node and then extending
the Oracle Database home. In other words, you extend the software onto the new node
in the same order as you installed the clusterware and Oracle database software
components on the existing two-node RAC.
During the creation of the existing two-node cluster, the installation of Oracle
Clusterware and the Oracle Database software were only performed from one node in the
RAC cluster — namely from linux1 as the oracle user account.
The Oracle Universal Installer (OUI) on that particular node would then use the
ssh and scp commands to run remote commands on and
copy files (the Oracle software) to all other nodes within the RAC cluster.
The oracle user account on the node running the OUI
(runInstaller) had to be trusted by all other nodes in the
RAC cluster. This meant that the oracle user account had to
run the secure shell commands (ssh or scp) on the
Linux server executing the OUI (linux1) against all other Linux servers in
the cluster without being prompted for a password. The same security requirements hold
true for this article. User equivalence will be configured so that the
Oracle Clusterware and Oracle Database
software will be securely copied from linux1 to the new Oracle RAC node
(linux3) using ssh and scp without being prompted for a password.
All shared disk storage for the existing Oracle RAC is based on
iSCSI
using a Network Storage Server; namely
Openfiler Release 2.2 (respin 2). Powered by
rPath Linux,
Openfiler
is a free browser-based network storage management utility that delivers file-based
Network Attached Storage (NAS) and block-based Storage Area Networking (SAN) in a single framework.
Openfiler supports CIFS, NFS, HTTP/DAV, FTP, however, we will only be making use of its
iSCSI capabilities to implement an inexpensive SAN for the shared storage components
required by Oracle RAC 10g.
This solution offers a low-cost alternative to fibre channel
for testing and educational purposes, but given the
low-end hardware being used, it should not be used in a production environment.
These articles provide a low cost alternative for those who want
to become familiar with Oracle RAC 10g using commercial off
the shelf components and downloadable software. Bear in mind that
these articles are provided for educational purposes only so the
setup is kept simple to demonstrate ideas and concepts. For example,
the disk mirroring configured in this article will be setup on one
physical disk only, while in practice that should be performed on
multiple physical drives. In addition, each Linux node will
only be configured with two network cards — one for
the public network (eth0) and one for the private cluster interconnect
"and" network storage server for shared iSCSI access (eth1).
For a production RAC implementation, the private interconnect should be at
least gigabit (or more) and "only" be used by Oracle
to transfer Cluster Manager and Cache Fusion related data. A third
dedicated network interface (i.e. eth2) should be configured on another
gigabit network for access to the network storage server (Openfiler).
)
While this article provides comprehensive instructions for successfully adding a node to
an existing Oracle RAC 10g system, it is by no means a substitute for the official
Oracle documentation. In addition to this article, users should also consult the following
Oracle documents to gain a full understanding of alternative configuration options, installation, and
administration with Oracle RAC 10g. Oracle's official documentation site is
docs.oracle.com.
Oracle Clusterware and Oracle Real Application Clusters Installation Guide - 10g Release 2 (10.2) for Linux
Oracle Clusterware and Oracle Real Application Clusters Administration and Deployment Guide - 10g Release 2 (10.2)
2 Day + Real Application Clusters Guide - 10g Release 2 (10.2)
The hardware used in this article to build the third node (linux3)
consists of a Linux workstation and components
which can be purchased at many local computer stores or over the Internet.
Oracle RAC Node 3 - (linux3)
Dell Dimension 3000 Series
- 2GB DDR SDRAM (at 333MHz)
- 60GB 7200 RPM Internal Hard Drive
- Integrated Intel 3D AGP Graphics
- Integrated 10/100 Ethernet - (Broadcom BCM4401)
- CDROM (48X Max Variable)
- 3.5" Floppy
- No Keyboard, Monitor, or Mouse - (Connected to KVM Switch)
US$300
1 - Ethernet LAN Card
Intel 10/100/1000Mbps PCI Desktop Adapter - (PWLA8391GT)
US$35
2 - Network Cables
Category 5e patch cable - (Connect linux3 to public network)
Category 5e patch cable - (Connect linux3 to interconnect ethernet switch)
US$5
US$5
Total
US$345
We are about to start the installation process.
As we start to go into the details of the
installation, it should be noted that most of the tasks within this
document will need to be performed on the new Oracle RAC node (linux3).
I will indicate at the beginning of each section whether or not the task(s)
should be performed on the new Oracle RAC node, the current Oracle RAC node(s),
or on the network storage server (openfiler1).
Perform the following installation on the new Oracle RAC node!
Downloading CentOS
Use the links (below) to download CentOS 4.5. After
downloading CentOS, you will then want to burn each of the ISO images
to CD.
If you are downloading the above ISO files to a MS Windows machine,
there are many options for burning these images (ISO files) to a CD. You
may already be familiar with and have the proper software
to burn images to CD. If you are not familiar with this process
and do not have the required software to burn images to CD, here are just
two (of many) software packages that can be used:
Installing CentOS
This section provides a summary of the screens used to install
CentOS. For more detailed installation instructions, it
is possible to use the manuals from Red Hat Linux
http://www.redhat.com/docs/manuals/.
I would suggest, however, that the instructions I have provided
below be used for this Oracle RAC 10g configuration.
Before installing the Linux operating system on the new Oracle RAC node,
you should have the two NIC interfaces (cards) installed.
The first screen is the CentOS boot screen.
At the boot: prompt, hit [Enter] to start the installation process.
Media Test
When asked to test the CD media, tab over to [Skip] and hit
[Enter]. If there
were any errors, the media burning software would have warned us. After several
seconds, the installer should then detect the video card, monitor, and mouse.
The installer then goes into GUI mode.
Welcome to CentOS
At the welcome screen, click [Next] to continue.
Language / Keyboard Selection
The next two screens prompt you for the Language and Keyboard
settings. In almost all cases, you can accept the defaults.
Make the appropriate selection for your configuration and click [Next] to continue.
Installation Type
Choose the [Custom] option and click [Next] to continue.
Disk Partitioning Setup
Select [Automatically partition] and click [Next] continue.
Partitioning
The installer will then allow you to view (and modify if needed) the
disk partitions it automatically selected. For most automatic layouts, the
installer will choose 100MB for /boot, double the amount of RAM (systems with < 2GB RAM)
or an amount equal to RAM (systems with > 2GB RAM) for swap, and the rest going to the
root (/) partition. Starting with EL 4, the installer
will create the same disk configuration as just noted but will create
them using the Logical Volume Manager (LVM). For example, it will
partition the first hard drive (/dev/hda for my configuration) into two
partitions — one for the /boot partition (/dev/hda1) and the
remainder of the disk dedicate to a LVM named VolGroup00 (/dev/hda2).
The LVM Volume Group (VolGroup00) is then partitioned into two LVM
partitions - one for the root filesystem (/) and another for swap.
Boot Loader Configuration
Available RAM
Swap Space Required
Between 1 GB and 2 GB
1.5 times the size of RAM
Between 2 GB and 8 GB
Equal to the size of RAM
More than 8 GB
.75 times the size of RAM
The installer will use the GRUB boot loader by default.
To use the GRUB boot loader, accept all default values and click [Next] to continue.
Network Configuration
I made sure to install both NIC interfaces (cards) in the
new Linux machine before starting the operating system installation.
This screen should have successfully detected each of the network
devices.
Firewall
- Check OFF the option to [Configure using DHCP]
- Leave the [Activate on boot] checked ON
- IP Address: 192.168.1.107
- Netmask: 255.255.255.0
- Check OFF the option to [Configure using DHCP]
- Leave the [Activate on boot] checked ON
- IP Address: 192.168.2.107
- Netmask: 255.255.255.0
On this screen, make sure to select [No firewall].
Also under the option to "Enable SELinux?",
select [Disabled] and click [Next] to continue.
Additional Language Support / Time Zone
The next two screens allow you to select additional language support
and time zone information.
In almost all cases, you can accept the defaults.
Make the appropriate selection for your configuration and click [Next] to continue.
Set Root Password
Select a root password and click [Next] to continue.
Package Group Selection
Scroll down to the bottom of this screen and select
[Everything] under the "Miscellaneous" section. Click
[Next] to continue.
About to Install
This screen is basically a confirmation screen. Click [Next]
on this screen and then the [Continue] button on the dialog box
to start the installation. During the installation process,
you will be asked to switch disks to Disk #2, Disk #3, and then Disk #4.
Graphical Interface (X) Configuration
With most RHEL 4 distributions (not the case with CentOS 4.5), when the installation
is complete, the installer will attempt to detect
your video hardware. Ensure that the installer has detected
and selected the correct video hardware (graphics card and monitor) to
properly use the X Windows server. You will continue with the X
configuration in the next serveral screens.
Congratulations
And that's it. You have successfully installed CentOS
on the new Oracle RAC node (linux3). The installer will eject the CD
from the CD-ROM drive. Take out the CD and click [Reboot] to reboot
the system.
Perform the following network configuration tasks on the new Oracle RAC node!
Introduction to Network Settings
Although we configured several of the network
settings during the installation of CentOS, it is important
to not skip this section as it contains critical
steps that are required for a successful RAC environment.
Configuring Public and Private Network
With the new Oracle RAC node, we need to configure the network
for access to the public network as well as the private interconnect.
# su -
# /usr/bin/system-config-network &
Do not use DHCP naming for the public IP address or the interconnects - we need static IP addresses!
/etc/hosts file on all nodes
in the RAC cluster. Both of these tasks can
be completed using the Network Configuration GUI.
/etc/hosts entries will be the same for all three
Oracle RAC nodes
(linux1, linux2, and linux3)
as well as the network storage server (openfiler1):
Oracle RAC Node 3 - (linux3)
Device
IP Address
Subnet
Gateway
Purpose
eth0
192.168.1.107
255.255.255.0
192.168.1.1
Connects linux3 to the public network
eth1
192.168.2.107
255.255.255.0
Connects linux3 (interconnect) to linux1/linux2 (linux1-priv/linux2-priv)
/etc/hosts
127.0.0.1 localhost.localdomain localhost
# Public Network - (eth0)
192.168.1.100 linux1
192.168.1.101 linux2
192.168.1.107 linux3
# Private Interconnect - (eth1)
192.168.2.100 linux1-priv
192.168.2.101 linux2-priv
192.168.2.107 linux3-priv
# Public Virtual IP (VIP) addresses - (eth0:1)
192.168.1.200 linux1-vip
192.168.1.201 linux2-vip
192.168.1.207 linux3-vip
# Private Storage Network for Openfiler
192.168.1.195 openfiler1
192.168.2.195 openfiler1-priv
Oracle RAC Node 2 - (linux2)
Device
IP Address
Subnet
Gateway
Purpose
eth0
192.168.1.101
255.255.255.0
192.168.1.1
Connects linux2 to the public network
eth1
192.168.2.101
255.255.255.0
Connects linux2 (interconnect) to linux1/linux3 (linux1-priv/linux3-priv)
/etc/hosts
127.0.0.1 localhost.localdomain localhost
# Public Network - (eth0)
192.168.1.100 linux1
192.168.1.101 linux2
192.168.1.107 linux3
# Private Interconnect - (eth1)
192.168.2.100 linux1-priv
192.168.2.101 linux2-priv
192.168.2.107 linux3-priv
# Public Virtual IP (VIP) addresses - (eth0:1)
192.168.1.200 linux1-vip
192.168.1.201 linux2-vip
192.168.1.207 linux3-vip
# Private Storage Network for Openfiler
192.168.1.195 openfiler1
192.168.2.195 openfiler1-priv
Oracle RAC Node 1 - (linux1)
Device
IP Address
Subnet
Gateway
Purpose
eth0
192.168.1.100
255.255.255.0
192.168.1.1
Connects linux1 to the public network
eth1
192.168.2.100
255.255.255.0
Connects linux1 (interconnect) to linux2/linux3 (linux2-priv/linux3-priv)
/etc/hosts
127.0.0.1 localhost.localdomain localhost
# Public Network - (eth0)
192.168.1.100 linux1
192.168.1.101 linux2
192.168.1.107 linux3
# Private Interconnect - (eth1)
192.168.2.100 linux1-priv
192.168.2.101 linux2-priv
192.168.2.107 linux3-priv
# Public Virtual IP (VIP) addresses - (eth0:1)
192.168.1.200 linux1-vip
192.168.1.201 linux2-vip
192.168.1.207 linux3-vip
# Private Storage Network for Openfiler
192.168.1.195 openfiler1
192.168.2.195 openfiler1-priv
In the screen shots below, only the new Oracle RAC node (linux3) is shown. Ensure
that the /etc/hosts file is updated on all participating nodes to access the
new Oracle RAC node!
Figure 2: Network Configuration Screen - Node 3 (linux3)
Figure 3: Ethernet Device Screen - eth0 (linux3)
Figure 4: Ethernet Device Screen - eth1 (linux3)
Figure 5: Network Configuration Screen - /etc/hosts (linux3)
Once the network is configured, you can use the ifconfig
command to verify everything is working. The following example
is from the new Oracle RAC node linux3:
# /sbin/ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:1E:2A:37:6B:9E
inet addr:192.168.1.107 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::21e:2aff:fe37:6b9e/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1167677 errors:0 dropped:0 overruns:0 frame:0
TX packets:1842517 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:576629131 (549.9 MiB) TX bytes:2143836310 (1.9 GiB)
Interrupt:209 Base address:0xef00
eth1 Link encap:Ethernet HWaddr 00:0E:0C:C0:78:64
inet addr:192.168.2.107 Bcast:192.168.2.255 Mask:255.255.255.0
inet6 addr: fe80::20e:cff:fec0:7864/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:48 errors:0 dropped:0 overruns:0 frame:0
TX packets:59 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:4782 (4.6 KiB) TX bytes:5564 (5.4 KiB)
Base address:0xdd80 Memory:fe9c0000-fe9e0000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:2034 errors:0 dropped:0 overruns:0 frame:0
TX packets:2034 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2386686 (2.2 MiB) TX bytes:2386686 (2.2 MiB)
sit0 Link encap:IPv6-in-IPv4
NOARP MTU:1480 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
Verify Network Access to All Nodes
Verify that the new Oracle RAC node has access to the public and
private network for all current nodes. From linux3:
# ping -c 1 linux1 | grep '1 packets transmitted'
1 packets transmitted, 1 received, 0% packet loss, time 0ms
# ping -c 1 linux1-priv | grep '1 packets transmitted'
1 packets transmitted, 1 received, 0% packet loss, time 0ms
# ping -c 1 linux2 | grep '1 packets transmitted'
1 packets transmitted, 1 received, 0% packet loss, time 0ms
# ping -c 1 linux2-priv | grep '1 packets transmitted'
1 packets transmitted, 1 received, 0% packet loss, time 0ms
# ping -c 1 openfiler1 | grep '1 packets transmitted'
1 packets transmitted, 1 received, 0% packet loss, time 0ms
# ping -c 1 openfiler1-priv | grep '1 packets transmitted'
1 packets transmitted, 1 received, 0% packet loss, time 0ms
Confirm the RAC Node Name is Not Listed in Loopback Address
Ensure that the new Oracle RAC node (linux3) is
not included for the loopback address in the /etc/hosts file.
If the machine name is listed in the in the loopback address entry as below:
127.0.0.1 linux3 localhost.localdomain localhost
it will need to be removed as shown below:
127.0.0.1 localhost.localdomain localhost
If the RAC node name is listed for the loopback address, you will
receive the following error during the RAC installation:
ORA-00603: ORACLE server session terminated by fatal error
or
ORA-29702: error occurred in Cluster Group Service operation
Confirm localhost is defined in the /etc/hosts file for the loopback address
Ensure that the entry for localhost.localdomain and localhost are
included for the loopback address in the /etc/hosts file for the new Oracle RAC node:
127.0.0.1 localhost.localdomain localhost
If an entry does not exist for localhost in the /etc/hosts
file, Oracle Clusterware will be unable to start the application resources — notably the ONS process.
The error would indicate "Failed to get IP for localhost"
and will be written to the log file for ONS. For example:
CRS-0215 could not start resource 'ora.linux3.ons'. Check log file
"/u01/app/crs/log/linux3/racg/ora.linux3.ons.log"
for more details.
The ONS log file will contain lines similar to the following:
2007-04-14 13:10:02.729: [ RACG][3086871296][13316][3086871296][ora.linux3.ons]: Failed to get IP for localhost (1)
Failed to get IP for localhost (1)
Failed to get IP for localhost (1)
onsctl: ons failed to start
...
Adjusting Network Settings
With Oracle 9.2.0.1 and onwards, Oracle now makes use of UDP as the default protocol
on Linux for inter-process communication (IPC), such as Cache Fusion
and Cluster Manager buffer transfers
between instances within the RAC cluster.
# +---------------------------------------------------------+
# | ADJUSTING NETWORK SETTINGS |
# +---------------------------------------------------------+
# | With Oracle 9.2.0.1 and onwards, Oracle now makes use |
# | of UDP as the default protocol on Linux for |
# | inter-process communication (IPC), such as Cache Fusion |
# | and Cluster Manager buffer transfers between instances |
# | within the RAC cluster. Oracle strongly suggests to |
# | adjust the default and maximum receive buffer size |
# | (SO_RCVBUF socket option) to 256 KB, and the default |
# | and maximum send buffer size (SO_SNDBUF socket option) |
# | to 256 KB. The receive buffers are used by TCP and UDP |
# | to hold received data until it is read by the |
# | application. The receive buffer cannot overflow because |
# | the peer is not allowed to send data beyond the buffer |
# | size window. This means that datagrams will be |
# | discarded if they don't fit in the socket receive |
# | buffer. This could cause the sender to overwhelm the |
# | receiver. |
# +---------------------------------------------------------+
# +---------------------------------------------------------+
# | Default setting in bytes of the socket "receive" buffer |
# | which may be set by using the SO_RCVBUF socket option. |
# +---------------------------------------------------------+
net.core.rmem_default=262144
# +---------------------------------------------------------+
# | Maximum setting in bytes of the socket "receive" buffer |
# | which may be set by using the SO_RCVBUF socket option. |
# +---------------------------------------------------------+
net.core.rmem_max=262144
# +---------------------------------------------------------+
# | Default setting in bytes of the socket "send" buffer |
# | which may be set by using the SO_SNDBUF socket option. |
# +---------------------------------------------------------+
net.core.wmem_default=262144
# +---------------------------------------------------------+
# | Maximum setting in bytes of the socket "send" buffer |
# | which may be set by using the SO_SNDBUF socket option. |
# +---------------------------------------------------------+
net.core.wmem_max=262144
Then, ensure that each of these parameters are truly in
effect by running the following command on the new Oracle RAC node:
# sysctl -p
net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.core.rmem_default = 262144
net.core.rmem_max = 262144
net.core.wmem_default = 262144
net.core.wmem_max = 262144
Check and turn off UDP ICMP rejections:
During the Linux installation process, I indicated to not configure the
firewall option. (By default the option to configure a firewall is selected
by the installer.)
This has burned me several times so I like to do a double-check that the firewall
option is not configured and to ensure udp ICMP filtering is turned off.
08/29/2005 22:17:19
oac_init:2: Could not connect to server, clsc retcode = 9
08/29/2005 22:17:19
a_init:12!: Client init unsuccessful : [32]
ibctx:1:ERROR: INVALID FORMAT
proprinit:problem reading the bootblock or superbloc 22
When experiencing this type of error, the solution is to remove the udp ICMP (iptables)
rejection rule - or to simply have the firewall option turned off.
The Oracle Clusterware software will then start to operate normally and not crash. The following commands
should be executed as the root user account:
# /etc/rc.d/init.d/iptables status
Firewall is stopped.
# /etc/rc.d/init.d/iptables stop
Flushing firewall rules: [ OK ]
Setting chains to policy ACCEPT: filter [ OK ]
Unloading iptables modules: [ OK ]
# chkconfig iptables off
Perform the following configuration tasks on the network storage server (openfiler1)!
https://openfiler1:446/
From the Openfiler Storage Control Center home page, login as
an administrator. The default administration login credentials
for Openfiler are:
Services
This article assumes that the current Oracle RAC 10g environment is
operational and therefore the iSCSI services should already be enabled within
Openfiler.
Figure 6: Verify iSCSI Services are Enabled
[root@openfiler1 ~]# service iscsi-target status
ietd (pid 3784) is running...
Network Access Restriction
The next step is to configure network access in Openfiler so
that the new Oracle RAC node (linux3) has permissions to the shared iSCSI volumes
used in the current Oracle RAC 10g environment.
Figure 7: Configure Openfiler Host Access for new Oracle RAC Node
Current Logical iSCSI Volumes
The current Openfiler configuration contains five logical iSCSI volumes
in a single volume group named rac1.
iSCSI / Logical Volumes in Volume Group rac1
Volume Name
Volume Description
Required Space (MB)
Filesystem Type
crs
Oracle Clusterware
2,048
iSCSI
asm1
Oracle ASM Volume 1
118,720
iSCSI
asm2
Oracle ASM Volume 2
118,720
iSCSI
asm3
Oracle ASM Volume 3
118,720
iSCSI
asm4
Oracle ASM Volume 4
118,720
iSCSI
Figure 8: Current Logical (iSCSI) Volumes
Grant Access Rights to New Logical Volumes
Before an iSCSI client can have access to any of the iSCSI volumes, it needs
to be granted the appropriate permissions. In this section, we need to grant
access to each of the five local iSCSI volumes to the new Oracle RAC node linux3.
Figure 9: Grant Host Access to Logical (iSCSI) Volumes
Configure the iSCSI initiator on the new Oracle RAC node!
iSCSI (initiator) service
On the new Oracle RAC node, we have to make sure the iSCSI (initiator) service is
up and running.
If not installed as part of the operating system setup, the iscsi-initiator-utils RPM
(i.e. iscsi-initiator-utils-4.0.3.0-5.i386.rpm) should be downloaded and installed on the new Oracle RAC node.
The new Oracle RAC node must have the iscsi-initiator-utils RPM installed. To determine
if this package is installed, perform the following:
# rpm -qa | grep iscsi
iscsi-initiator-utils-4.0.3.0-5
If not installed, the iscsi-initiator-utils RPM package can be found on disk 3 of 4
of the RHEL4 Update 5 distribution or
downloaded
from one of the Internet RPM resources.
# rpm -Uvh iscsi-initiator-utils-4.0.3.0-5.i386.rpm
warning: iscsi-initiator-utils-4.0.3.0-5.i386.rpm:
V3 DSA signature: NOKEY, key ID 443e1821
Preparing... ########################################### [100%]
1:iscsi-initiator-utils ########################################### [100%]
...
DiscoveryAddress=openfiler1-priv
...
After making the change to the /etc/iscsi.conf file on the new Oracle RAC node,
we can start (or restart) the iscsi initiator service on that node:
# service iscsi restart
Searching for iscsi-based multipath maps
Found 0 maps
Stopping iscsid: iscsid not running
Checking iscsi config: [ OK ]
Loading iscsi driver: [ OK ]
Starting iscsid: [ OK ]
We should also configure the iSCSI service to be active across machine reboots for the new Oracle RAC node.
The Linux command chkconfig can be used to achieve that as follows:
# chkconfig --level 345 iscsi on
The iSCSI initiator service should now be configured and started on
the new Oracle RAC node. In the parent to this article
("Building an Inexpensive Oracle RAC 10g Release 2 on Linux - (CentOS 4.5 / iSCSI)"),
we needed go through the arduous task of mapping the iSCSI target
names discovered from Openfiler to the local SCSI device name on one
of the Oracle RAC nodes. Given that all five logical iSCSI volumes were
partitioned and formatted with labels in that article, we
don't have to perform that task again. Note that one of the iSCSI volumes
was formatted and labeled using OCFS2 while the other four were labeled
for use by ASM.
...
Jan 21 16:41:29 linux3 iscsi: iscsid startup succeeded
Jan 21 16:41:29 linux3 iscsid[13822]: Connected to Discovery Address 192.168.2.195
Jan 21 16:41:29 linux3 kernel: iscsi-sfnet:host0: Session established
Jan 21 16:41:29 linux3 kernel: iscsi-sfnet:host2: Session established
Jan 21 16:41:29 linux3 kernel: iscsi-sfnet:host1: Session established
Jan 21 16:41:29 linux3 kernel: scsi0 : SFNet iSCSI driver
Jan 21 16:41:29 linux3 kernel: scsi2 : SFNet iSCSI driver
Jan 21 16:41:29 linux3 kernel: scsi1 : SFNet iSCSI driver
Jan 21 16:41:29 linux3 kernel: Vendor: Openfile Model: Virtual disk Rev: 0
Jan 21 16:41:29 linux3 kernel: Type: Direct-Access ANSI SCSI revision: 04
Jan 21 16:41:29 linux3 kernel: SCSI device sda: 243138560 512-byte hdwr sectors (124487 MB)
Jan 21 16:41:29 linux3 kernel: SCSI device sda: drive cache: write through
Jan 21 16:41:29 linux3 kernel: Vendor: Openfile Model: Virtual disk Rev: 0
Jan 21 16:41:29 linux3 kernel: Type: Direct-Access ANSI SCSI revision: 04
Jan 21 16:41:29 linux3 kernel: SCSI device sda: 243138560 512-byte hdwr sectors (124487 MB)
Jan 21 16:41:29 linux3 kernel: iscsi-sfnet:host3: Session established
Jan 21 16:41:29 linux3 kernel: iscsi-sfnet:host4: Session established
Jan 21 16:41:29 linux3 kernel: scsi3 : SFNet iSCSI driver
Jan 21 16:41:29 linux3 kernel: SCSI device sda: drive cache: write through
Jan 21 16:41:29 linux3 kernel: sda: unknown partition table
Jan 21 16:41:29 linux3 kernel: Attached scsi disk sda at scsi0, channel 0, id 0, lun 0
Jan 21 16:41:29 linux3 kernel: Vendor: Openfile Model: Virtual disk Rev: 0
Jan 21 16:41:29 linux3 scsi.agent[13934]: disk at /devices/platform/host0/target0:0:0/0:0:0:0
Jan 21 16:41:29 linux3 kernel: Type: Direct-Access ANSI SCSI revision: 04
Jan 21 16:41:29 linux3 kernel: Vendor: Openfile Model: Virtual disk Rev: 0
Jan 21 16:41:29 linux3 kernel: Type: Direct-Access ANSI SCSI revision: 04
Jan 21 16:41:29 linux3 kernel: scsi4 : SFNet iSCSI driver
Jan 21 16:41:29 linux3 kernel: SCSI device sdb: 243138560 512-byte hdwr sectors (124487 MB)
Jan 21 16:41:29 linux3 kernel: Vendor: Openfile Model: Virtual disk Rev: 0
Jan 21 16:41:29 linux3 kernel: Type: Direct-Access ANSI SCSI revision: 04
Jan 21 16:41:29 linux3 kernel: SCSI device sdb: drive cache: write through
Jan 21 16:41:29 linux3 scsi.agent[13983]: disk at /devices/platform/host2/target2:0:0/2:0:0:0
Jan 21 16:41:29 linux3 scsi.agent[13996]: disk at /devices/platform/host3/target3:0:0/3:0:0:0
Jan 21 16:41:30 linux3 kernel: SCSI device sdb: 243138560 512-byte hdwr sectors (124487 MB)
Jan 21 16:41:30 linux3 kernel: SCSI device sdb: drive cache: write through
Jan 21 16:41:30 linux3 kernel: sdb: unknown partition table
Jan 21 16:41:30 linux3 kernel: Attached scsi disk sdb at scsi2, channel 0, id 0, lun 0
Jan 21 16:41:30 linux3 kernel: SCSI device sdc: 243138560 512-byte hdwr sectors (124487 MB)
Jan 21 16:41:30 linux3 kernel: SCSI device sdc: drive cache: write through
Jan 21 16:41:30 linux3 kernel: SCSI device sdc: 243138560 512-byte hdwr sectors (124487 MB)
Jan 21 16:41:30 linux3 kernel: SCSI device sdc: drive cache: write through
Jan 21 16:41:30 linux3 kernel: sdc: unknown partition table
Jan 21 16:41:30 linux3 kernel: Attached scsi disk sdc at scsi3, channel 0, id 0, lun 0
Jan 21 16:41:30 linux3 kernel: SCSI device sdd: 243138560 512-byte hdwr sectors (124487 MB)
Jan 21 16:41:30 linux3 kernel: SCSI device sdd: drive cache: write through
Jan 21 16:41:30 linux3 kernel: SCSI device sdd: 243138560 512-byte hdwr sectors (124487 MB)
Jan 21 16:41:30 linux3 kernel: SCSI device sdd: drive cache: write through
Jan 21 16:41:30 linux3 kernel: sdd: unknown partition table
Jan 21 16:41:30 linux3 kernel: Attached scsi disk sdd at scsi1, channel 0, id 0, lun 0
Jan 21 16:41:30 linux3 kernel: SCSI device sde: 4194304 512-byte hdwr sectors (2147 MB)
Jan 21 16:41:30 linux3 scsi.agent[14032]: disk at /devices/platform/host4/target4:0:0/4:0:0:0
Jan 21 16:41:30 linux3 scsi.agent[14045]: disk at /devices/platform/host1/target1:0:0/1:0:0:0
Jan 21 16:41:30 linux3 kernel: SCSI device sde: drive cache: write through
Jan 21 16:41:30 linux3 kernel: SCSI device sde: 4194304 512-byte hdwr sectors (2147 MB)
Jan 21 16:41:30 linux3 kernel: SCSI device sde: drive cache: write through
Jan 21 16:41:30 linux3 kernel: sde: unknown partition table
Jan 21 16:41:30 linux3 kernel: Attached scsi disk sde at scsi4, channel 0, id 0, lun 0
...
The above entries show that the client (linux3) was able to establish
the iSCSI sessions with the iSCSI storage server (openfiler1-priv at 192.168.2.195).
iscsi-ls-map.sh # ---------------------
# FILE: iscsi-ls-map.sh
# ---------------------
RUN_USERID=root
export RUN_USERID
RUID=`id | awk -F\( '{print $2}'|awk -F\) '{print $1}'`
if [[ ${RUID} != "$RUN_USERID" ]];then
echo " "
echo "You must be logged in as $RUN_USERID to run this script."
echo "Exiting script."
echo " "
exit 1
fi
dmesg | grep "^Attach" \
| awk -F" " '{ print "/dev/"$4 " " $6 }' \
| sed -e 's/,//' | sed -e 's/scsi//' \
| sort -n -k2 \
| sed -e '/disk1/d' > /tmp/tmp_scsi_dev
iscsi-ls | egrep -e "TARGET NAME" -e "HOST ID" \
| awk -F" " '{ if ($0 ~ /^TARGET.*/) printf $4; if ( $0 ~ /^HOST/) printf " %s\n",$4}' \
| sort -n -k2 \
| cut -d':' -f2- \
| cut -d'.' -f2- > /tmp/tmp_scsi_targets
join -t" " -1 2 -2 2 /tmp/tmp_scsi_dev /tmp/tmp_scsi_targets > MAP
echo "Host / SCSI ID SCSI Device Name iSCSI Target Name"
echo "---------------- ----------------------- -----------------"
cat MAP | sed -e 's/ / /g'
rm -f MAP# ./iscsi-ls-map.sh
Host / SCSI ID SCSI Device Name iSCSI Target Name
---------------- ------------------------ -----------------
0 /dev/sda asm4
1 /dev/sdd asm3
2 /dev/sdb asm2
3 /dev/sdc asm1
4 /dev/sde crs
Perform the following tasks on the new Oracle RAC node!
This guide adheres
to the Optimal Flexible Architecture (OFA) for naming conventions used
in creating the directory structure.
Create Group and User for Oracle
Lets start this section by creating the UNIX
oinstall and dba group
and oracle user account:
# groupadd -g 501 oinstall
# groupadd -g 502 dba
# useradd -m -u 501 -g oinstall -G dba -d /home/oracle -s /bin/bash -c "Oracle Software Owner" oracle
# id oracle
uid=501(oracle) gid=501(oinstall) groups=501(oinstall),502(dba)
Set the password for the oracle account:
# passwd oracle
Changing password for user oracle.
New UNIX password: xxxxxxxxxxx
Retype new UNIX password: xxxxxxxxxxx
passwd: all authentication tokens updated successfully.
Verify That the User nobody Exists
Before installing the Oracle software, complete the following procedure to verify that the user
nobody exists on the system:
# id nobody
uid=99(nobody) gid=99(nobody) groups=99(nobody)
If this command displays information about the nobody user, then you do not
have to create that user.
# /usr/sbin/useradd nobody
Create the Oracle Base Directory
The next step is to create a new directory that will be used to store
the Oracle Database software. When configuring the
oracle user's environment (later in this section) we will be assigning
the location of this directory to the $ORACLE_BASE environment variable.
# mkdir -p /u01/app/oracle
# chown -R oracle:oinstall /u01/app/oracle
# chmod -R 775 /u01/app/oracle
Create the Oracle Clusterware Home Directory
Next, create a new directory that will be used to store
the Oracle Clusterware software. When configuring the
oracle user's environment (later in this section) we will be assigning
the location of this directory to the $ORA_CRS_HOME environment variable.
# mkdir -p /u01/app/crs
# chown -R oracle:oinstall /u01/app/crs
# chmod -R 775 /u01/app/crs
Create Mount Point for OCFS2 / Clusterware
Let's now create the mount point for the Oracle Cluster File System, Release 2 (OCFS2)
that will be used to store the two Oracle Clusterware shared files.
# mkdir -p /u02
# chown -R oracle:oinstall /u02
# chmod -R 775 /u02
Create Login Script for oracle User Account
To ensure that the environment is setup correctly for the "oracle" UNIX
userid on the new Oracle RAC node, use the following .bash_profile:
When you are setting the Oracle environment variables for each Oracle RAC node, ensure to
assign each RAC node a unique Oracle SID!
# su - oracle
.bash_profile for Oracle User # .bash_profile
# Get the aliases and functions
if [ -f ~/.bashrc ]; then
. ~/.bashrc
fi
alias ls="ls -FA"
export JAVA_HOME=/usr/local/java
# User specific environment and startup programs
export ORACLE_BASE=/u01/app/oracle
export ORACLE_HOME=$ORACLE_BASE/product/10.2.0/db_1
export ORA_CRS_HOME=/u01/app/crs
export ORACLE_PATH=$ORACLE_BASE/common/oracle/sql:.:$ORACLE_HOME/rdbms/admin
export CV_JDKHOME=/usr/local/java
# Each RAC node must have a unique ORACLE_SID. (i.e. orcl1, orcl2, orcl3,...)
export ORACLE_SID=orcl3
export PATH=.:${JAVA_HOME}/bin:${PATH}:$HOME/bin:$ORACLE_HOME/bin
export PATH=${PATH}:/usr/bin:/bin:/usr/bin/X11:/usr/local/bin
export PATH=${PATH}:$ORACLE_BASE/common/oracle/bin
export ORACLE_TERM=xterm
export TNS_ADMIN=$ORACLE_HOME/network/admin
export ORA_NLS10=$ORACLE_HOME/nls/data
export LD_LIBRARY_PATH=$ORACLE_HOME/lib
export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:$ORACLE_HOME/oracm/lib
export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:/lib:/usr/lib:/usr/local/lib
export CLASSPATH=$ORACLE_HOME/JRE
export CLASSPATH=${CLASSPATH}:$ORACLE_HOME/jlib
export CLASSPATH=${CLASSPATH}:$ORACLE_HOME/rdbms/jlib
export CLASSPATH=${CLASSPATH}:$ORACLE_HOME/network/jlib
export THREADS_FLAG=native
export TEMP=/tmp
export TMPDIR=/tmp
Perform the following tasks on the new Oracle RAC node!
Swap Space Considerations
(An inadequate amount of swap during the installation
will cause the Oracle Universal Installer to either "hang" or "die")
# cat /proc/meminfo | grep MemTotal
MemTotal: 2074428 kB
# cat /proc/meminfo | grep SwapTotal
SwapTotal: 2031608 kB
# dd if=/dev/zero of=tempswap bs=1k count=500000
# chmod 600 tempswap
# mke2fs tempswap
# mkswap tempswap
# swapon tempswap
Configuring Kernel Parameters and Shell Limits
The kernel parameters and shell limits presented in this section are recommended values
only as documented by Oracle. For production database systems, Oracle recommends that
you tune these values to optimize the performance of the system.
Setting Shared Memory / Semaphores / File Handles / Local IP Range
Set the following kernel parameters in the
/etc/sysctl.conf file on the new Oracle RAC node.
cat >> /etc/sysctl.conf <<EOF
# +---------------------------------------------------------+
# | ADJUSTING ADDITIONAL KERNEL PARAMETERS FOR ORACLE |
# +---------------------------------------------------------+
# | Configure the kernel parameters for all Oracle Linux |
# | servers by setting shared memory and semaphores, |
# | setting the maximum amount of file handles, and setting |
# | the IP local port range. |
# +---------------------------------------------------------+
# +---------------------------------------------------------+
# | SHARED MEMORY |
# +---------------------------------------------------------+
kernel.shmmax=2147483648
# +---------------------------------------------------------+
# | SEMAPHORES |
# | ---------- |
# | |
# | SEMMSL_value SEMMNS_value SEMOPM_value SEMMNI_value |
# | |
# +---------------------------------------------------------+
kernel.sem=250 32000 100 128
# +---------------------------------------------------------+
# | FILE HANDLES |
# ----------------------------------------------------------+
fs.file-max=65536
# +---------------------------------------------------------+
# | LOCAL IP RANGE |
# ----------------------------------------------------------+
net.ipv4.ip_local_port_range=1024 65000
EOF
Setting Shell Limits for the oracle User
To improve the performance of the software on Linux systems, Oracle recommends you increase the
following shell limits for the oracle user:
Shell Limit
Item in limits.conf
Hard Limit
Maximum number of open file descriptors
nofile
65536
Maximum number of processes available to a single user
nproc
16384
cat >> /etc/security/limits.conf <<EOF
oracle soft nproc 2047
oracle hard nproc 16384
oracle soft nofile 1024
oracle hard nofile 65536
EOF
cat >> /etc/pam.d/login <<EOF
session required /lib/security/pam_limits.so
EOF
Update the default shell startup file for the "oracle" UNIX account.
cat >> /etc/profile <<EOF
if [ \$USER = "oracle" ]; then
if [ \$SHELL = "/bin/ksh" ]; then
ulimit -p 16384
ulimit -n 65536
else
ulimit -u 16384 -n 65536
fi
umask 022
fi
EOF
cat >> /etc/csh.login <<EOF
if ( \$USER == "oracle" ) then
limit maxproc 16384
limit descriptors 65536
endif
EOF
Activating All Kernel Parameters for the System
At this point, we have covered all of the required Linux kernel parameters needed
for a successful Oracle installation and configuration. The sections above
configured the Linux system to persist each of the kernel parameters through reboots on system
startup by placing them all in the /etc/sysctl.conf file.
# sysctl -p
net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.core.rmem_default = 262144
net.core.rmem_max = 262144
net.core.wmem_default = 262144
net.core.wmem_max = 262144
kernel.shmmax = 2147483648
kernel.sem = 250 32000 100 128
fs.file-max = 65536
net.ipv4.ip_local_port_range = 1024 65000
Setting the Correct Date and Time on the new Oracle RAC Node
When adding the new Oracle RAC node to the cluster, the Oracle Universal Installer (OUI) copies
the Oracle Clusterware and Oracle Database software from the source RAC node
(linux1 in this article) to the new node in the cluster
(linux3). During the remote copy process, the OUI will execute the UNIX
"tar" command on the remote node (linux3) to extract the files that were archived and
copied over. If the date and time on the node performing the install is greater than
that of the node it is copying to, the OUI will throw an error from the
"tar" command indicating it is attempting to extract files stamped with a time in the future:
Error while copying directory
/u01/app/crs with exclude file list 'null' to nodes 'linux3'.
[PRKC-1002 : All the submitted commands did not execute successfully]
---------------------------------------------
linux3:
/bin/tar: ./bin/lsnodes: time stamp 2008-02-13 09:21:34 is 735 s in the future
/bin/tar: ./bin/olsnodes: time stamp 2008-02-13 09:21:34 is 735 s in the future
...(more errors on this node)
# date
Thu Feb 14 00:17:00 EST 2008
# date -s "2/14/2008 00:17:20"
Perform the following tasks on the new Oracle RAC node!
The hangcheck-timer.ko Module
The hangcheck-timer module uses a kernel-based timer that
periodically checks the system task scheduler to catch delays in order to
determine the health of the system. If the system hangs or pauses, the timer
resets the node. The hangcheck-timer module uses the Time Stamp Counter
(TSC) CPU register which is a counter that is incremented at each clock signal.
The TCS offers much more accurate time measurements since this register
is updated by the hardware automatically.
Installing the hangcheck-timer.ko Module
The hangcheck-timer was normally shipped only by Oracle, however, this
module is now included with Red Hat Linux AS starting with kernel versions
2.4.9-e.12 and higher. The hangcheck-timer should already be included.
Use the following to ensure that you have the module included:
# find /lib/modules -name "hangcheck-timer.ko"
/lib/modules/2.6.9-55.EL/kernel/drivers/char/hangcheck-timer.ko
In the above output, we care about the hangcheck timer object
(hangcheck-timer.ko) in the
/lib/modules/2.6.9-55.EL/kernel/drivers/char directory.
Configuring and Loading the hangcheck-timer Module
There are two key parameters to the hangcheck-timer module:
The two hangcheck-timer module parameters indicate how long a RAC node
must hang before it will reset the system. A node reset will occur when
the following is true:
system hang time > (hangcheck_tick + hangcheck_margin)
Configuring Hangcheck Kernel Module Parameters
Each time the hangcheck-timer kernel module is loaded (manually or by Oracle) it needs to know what value to use for
each of the two parameters we just discussed: (hangcheck-tick and hangcheck-margin).
# su -
# echo "options hangcheck-timer hangcheck_tick=30 hangcheck_margin=180" >> /etc/modprobe.conf
Each time the hangcheck-timer kernel module gets loaded, it will use the values
defined by the entry I made in the /etc/modprobe.conf file.
Manually Loading the Hangcheck Kernel Module for Testing
Oracle is responsible for loading the hangcheck-timer kernel module when required. It is for this
reason that it is not required to perform a modprobe or insmod of the
hangcheck-timer kernel module in any of the startup files (i.e. /etc/rc.local).
# echo "/sbin/modprobe hangcheck-timer" >> /etc/rc.local
You don't have to manually load the hangcheck-timer kernel module using
modprobe or insmod after each reboot.
The hangcheck-timer module will be loaded by Oracle (automatically) when needed.
# su -
# modprobe hangcheck-timer
# grep Hangcheck /var/log/messages | tail -2
Feb 14 01:22:52 linux3 kernel: Hangcheck: starting hangcheck timer 0.9.0 (tick is 30 seconds, margin is 180 seconds).
Feb 14 01:22:52 linux3 kernel: Hangcheck: Using monotonic_clock().
Perform the following configuration procedures on linux1 and the new Oracle RAC node!
During the creation of the existing two-node cluster, the installation of Oracle
Clusterware and the Oracle Database software were only performed from one node in the
RAC cluster — namely from linux1 as the oracle user account.
The Oracle Universal Installer (OUI) on that particular node then would use the
ssh and scp commands to run remote commands on and
copy files (the Oracle software) to all other nodes within the RAC cluster.
The oracle user account on the node running the OUI
(runInstaller) had to be trusted by all other nodes in the
RAC cluster. This meant that the oracle user account had to
run the secure shell commands (ssh or scp) on the
Linux server executing the OUI against all other Linux servers in
the cluster without being prompted for a password. The same security requirements hold
true for this article. User equivalence will be configured so that the
Oracle Clusterware and Oracle Database
software will be securely copied from linux1 to the new Oracle RAC node
(linux3) using ssh and scp without being prompted for a password.
To determine if SSH is installed and running on the new Oracle RAC node,
enter the following command:
# pgrep sshd
3695
If SSH is running, then the response to this command is a list of process ID
number(s).
Creating the RSA Keys on the new Oracle RAC Node
The first step in configuring SSH is to create an RSA public/private key pair on
the new Oracle RAC node. An RSA public/private key should already exist on both of
the two nodes in the current two-node cluster. The command to do this will create a public
and private key for RSA (for a total of two keys per
node). The content of the RSA public keys will then be
copied into an authorized key file on linux1 which is then
distributed to all other Oracle RAC nodes in the cluster.
# su - oracle
$ mkdir -p ~/.ssh
$ chmod 700 ~/.ssh
$ /usr/bin/ssh-keygen -t rsa
At the prompts:
Updating and Distributing the "authorized key file" from linux1
Now that the new Oracle RAC node contains a public and private key for RSA,
you will need to update the authorized key file on
linux1 to add (append) the new RSA public key from linux3.
An authorized key file is nothing more than a single
file that contains a copy of everyone's (every node's) RSA public key.
Once the authorized key file contains all of the public
keys, it is then distributed to all other nodes in the cluster.
$ cd ~/.ssh
$ ls -l *.pub
-rw-r--r-- 1 oracle oinstall 223 Sep 2 01:18 id_rsa.pub
$ ssh linux3 cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
The authenticity of host 'linux3 (192.168.1.107)' can't be established.
RSA key fingerprint is f5:38:37:e8:84:4e:bd:6d:6b:25:f7:94:58:e8:b2:7a.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'linux3,192.168.1.107' (RSA) to the list of known hosts.
oracle@linux3's password: xxxxx
The first time you use SSH to
connect to a node from a particular system, you will see a message
similar to the following:
The authenticity of host 'linux3 (192.168.1.107)' can't be established.
RSA key fingerprint is f5:38:37:e8:84:4e:bd:6d:6b:25:f7:94:58:e8:b2:7a.
Are you sure you want to continue connecting (yes/no)? yes
Enter yes at the prompt to continue. You should
not see this message again when you connect from this system
to the same node.
$ scp ~/.ssh/authorized_keys linux2:.ssh/authorized_keys
Enter passphrase for key '/home/oracle/.ssh/id_rsa': xxxxx
authorized_keys 100% 669 0.7KB/s 00:00
$ scp ~/.ssh/authorized_keys linux3:.ssh/authorized_keys
oracle@linux3's password: xxxxx
authorized_keys 100% 669 0.7KB/s 00:00
$ chmod 600 ~/.ssh/authorized_keys
$ ssh linux3 hostname
Enter passphrase for key '/home/oracle/.ssh/id_rsa': xxxxx
linux3
If you see any other messages or text, apart from the host name,
then the Oracle installation can fail. Make any changes required
to ensure that only the host name is displayed when you enter
these commands. You should ensure that any part of a login script(s)
that generate any output, or ask any questions, are modified so that
they act only when the shell is an interactive shell.
Enabling SSH User Equivalency for the Current Shell Session
When running the addNode.sh script from linux1 (which runs the OUI), it will need to
run the secure shell tool commands (ssh and scp) on the new Oracle RAC node
without being prompted for a pass phrase. Even though SSH is now configured
on all Oracle RAC nodes in the cluster, using the secure shell tool commands will
still prompt for a pass phrase. Before running the addNode.sh script, you need to
enable user equivalence for the terminal session you plan to run the
script from. For the purpose of this article, the addNode.sh script
will be run from linux1.
# su - oracle
$ exec /usr/bin/ssh-agent $SHELL
$ /usr/bin/ssh-add
Enter passphrase for /home/oracle/.ssh/id_rsa: xxxxx
Identity added: /home/oracle/.ssh/id_rsa (/home/oracle/.ssh/id_rsa)
At the prompt, enter the pass phrase for each key that you generated.
$ ssh linux1 "date;hostname"
Fri Feb 22 12:13:57 EST 2008
linux1
$ ssh linux2 "date;hostname"
Fri Feb 22 12:14:43 EST 2008
linux2
$ ssh linux3 "date;hostname"
Fri Feb 2
