Recover Corrupt/Missing Oracle Cluster Registry (OCR) with No Backup - (Oracle 10g) It happens. Not very often, but it can happen. You are faced with a corrupt or missing Oracle Cluster Registry (OCR) and have no backup to recover from. So, how can something like this occur? We know that the CRSD process is responsible for creating backup copies of the OCR every 4 hours from the master node in the CRS_home/cdata directory. These backups are meant to be used to recoverthe OCR from a lost or corrupt OCR file using the ocrconfig -restore command, so how is it possible to be in a situation where the OCR needs to be recovered and you have no viable backup?

Well, consider a scenario where you add a node to the cluster and before the next backup (before 4 hours) you find the OCR has been corrupted. You may have forgotten to create a logical export of the OCR before adding the new node or worse yet, the logical export you took is also corrupt. In either case, you are left with a corrupt OCR and no recent backup. Talk about a bad day! Another possible scenario could be a shell script that wrongly deletes all available backups. Talk about an even worse day.

In the event the OCR is corrupt on one node and all options to recover it have failed, one safe way to re-create the OCR (and consequently the voting disk) is to reinstall the Oracle Clusterware software. In order to accomplish this, a complete outage is required for the entire cluster throughout the duration of the re-install. The Oracle Clusterware software will need to be fully removed, the OCR and voting disks reformatted, all virtual IP addresses (VIPs) de-installed, and a complete reinstall of the Oracle Clusterware software will need to be performed. It should also be noted that any patches that were applied to the original clusterware install will need to be re-applied. As you can see, having a backup of the OCR and voting disk can dramatically simplify the recovery of your system!

A second and much more efficient method used to re-create the OCR (and consequently the voting disk as well) is to re-run the root.sh script from the primary node in the cluster. This is described in Doc ID: 399482.1 on the My Oracle Support web site. The procedures actually call for running the rootdelete.sh and rootdeinstall.sh on all nodes in the cluster before running root.sh. In my opinion, this method is quicker and much less intrusive than reinstalling Oracle Clusterware and the one described in the following article:

Recover Corrupt/Missing Oracle Cluster Registry (OCR) with No Backup - (Oracle 10g)

Oracle Clusterware 10g, formerly known as Cluster Ready Services (CRS) is portable cluster software that allows clustering of single servers so that they cooperate as a single system. This infrastructure simplifies the requirement for an Oracle Real Application Clusters (RAC) database by providing cluster software that is tightly integrated with the Oracle Database.

The Oracle Clusterware requires two critical clusterware components: a voting disk to record node membership information and the Oracle Cluster Registry (OCR) to record cluster configuration information. Both components play an extremely important role in the overall health and availability of the cluster.

The following article provides a detailed look at how to administer the OCR and voting disk using illustrative examples and instructions on how to create a robust backup and recovery strategy. It is intended for DBAs, System Administrators, and Support Engineers tasked with supporting an Oracle RAC 10g environment. The examples described in this guide were tested with Oracle RAC 10g Release 2 (10.2.0.4) on the Linux x86 platform.

OCR File and Voting Disk Administration by Example - (Oracle 10g)

Reclaiming Unused LOB Space in Oracle Manually reclaiming unused space in a normal Oracle table is a fairly simple process and can be performed online starting with Oracle 10g R1.

What if, however, the table contains a LOB column that contains significant unused space? Starting with Oracle 10g R2, Oracle provides a solution that allows users to reclaim LOB space (LOB data and LOB index) and that is the topic of the following recently published article:

Reclaiming Unused LOB Space in Oracle

Starting with Oracle 11g, Fast Application Notification (FAN) can be used with SQL*Plus. With Oracle RAC 11g, you can specify the -F (FAILOVER) option to the sqlplus command. This enabled SQL*Plus to interact with the OCI failover mode in a Real Application Cluster (RAC) environment. In this mode, a service or instance failure is transparently handled with transaction status messages if applicable.

For an in-depth working example that describes the Fast Connection Failover (FCF) mechanism, please consult the following JDBC Java application:

Using FAN with SQL*Plus in Oracle 11g

Adding a Node to an Oracle RAC 10g Release 2 Cluster on Linux - (CentOS 5.3 / iSCSI) 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.

I recently published an extension to my article "Building an Inexpensive Oracle RAC 10g Release 2 on Linux - (CentOS 5.3 / 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 5.3 Linux, it should work unchanged with Red Hat Enterprise Linux 5 Update 3.

The new article can be accessed using the following link:

Add a Node to an Existing Oracle RAC 10g Release 2 Cluster on Linux - (CentOS 5.3 / iSCSI)

This week I published the latest in a series of articles on how to build an inexpensive Oracle RAC system. This article focuses on Oracle 10g Release 2 (10.2.0.1.0) as well as the latest version of CentOS (version 5.3).

As with its predecessor, this article provides detailed instructions on how to build a two-node Oracle RAC system using low cost hardware and freely available software. A network storage server will be built using Openfiler 2.3 (Final) and iSCSI technology which will be used for all shared storage requirements. 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, I will only be making use of its iSCSI capabilities to implement an inexpensive SAN for the shared storage component required by Oracle RAC 10g.

The newly updated Oracle RAC 10g / iSCSI article can be found at:

Building an Inexpensive Oracle RAC 10g Release 2 on Linux - (CentOS 5.3 / iSCSI)

In a follow-up to my recently published article "Installing Grid Control (10.2.0.5) on RHEL 5 with 11g Database Repository", I now provide a supplement to this guide on how to install and configure the Grid Control Management Agent (10.2.0.5). This new article provides one approach (out of several available) used to install and configure the Oracle Management Agent (10.2.0.5) on an Oracle database server node running the Red Hat Enterprise Linux 5 operating system.

This guide assumes you have a working Oracle Enterprise Manager 10g Grid Control Release 5 environment in place and running.

The new guide can be found at:

Installing Grid Control Management Agent (10.2.0.5)

I recently created an example JDBC class that provides a convenient template which demonstrates some of the more helpful JDBC API calls while using an Oracle Database. The methods defined in this class will be used to create a test table in the SCOTT schema named JDBC_EXAMPLE. A set of random values will then be inserted into the new table and then queried back using basic JDBC calls. The random values being used to populate the test table will come from the dictionary view ALL_OBJECTS.

This class is useful in demonstrating how to fetch integers, floating-point numbers, strings, and dates from a result set and furthermore, how to manipulate and print the data from the database. The example class also demonstrates how to calculate the run time of queries and DML calls (in milliseconds), format dates, and basic exception handling.

The class concludes by dropping the test table and then logging off from the database.

This new Java class can be accessed from the "Java Programming Examples" page which includes many other example Java classes.

From the left topics menu, select "Programming -> Java" and then from the "Java Programming Examples" page, scroll down to "JDBC -> JDBC Example".

You can also use the following URL to access the new Java class directly:

JdbcExample.java

Installing and configuring Oracle Enterprise Manager Grid Control has never been a straightforward task. The product itself is an overly complex and fragile web application with a considerable number of bugs. What makes matters worse is that the documentation for installing Enterprise Manager Grid Control is truly lacking. For many, the installation will consist of scattered bits and pieces found on My Oracle Support and from performing numerous Google searches.

In an attempt to put all of the pieces together to successfully install and configure the latest release of Grid Control (10.2.0.5), I published a step-by-step instruction guide. This guide will walk the reader through setting up the Linux O/S, performing pre-requisite tasks, downloading the required software, installing and patching Grid Control, configuring the newly installed Grid Control environment, and finally how to verify the Grid Control components are working properly.

The configuration will consist of the following components:

• Oracle Enterprise Manager 10g Grid Control Release 5 - (10.2.0.5)
• Red Hat Enterprise Linux 5 - (CentOS 5.3)
• Using an Existing 11g Database for the Management Repository

The newly published article can be found at:

Installing Grid Control (10.2.0.5) on RHEL 5 with 11g Database Repository

Back in January 2008, I published a comprehensive guide for installing Oracle Database 11g R1 on the Linux platform (RHEL 5). I recently updated this article to include a new section on how to download and install the most recent 11g Database Patch Set (11.1.0.7.0).

The updated article can be found at:

Installing Oracle Database 11g Release 1 on Linux - (RHEL 5)

Oracle Secure Backup (OSB) provides a reliable, centralized tape backup management solution which can be used to protect file system data as well as Oracle Database files. For Oracle Recovery Manager (RMAN) users, the Oracle Secure Backup SBT interface enables you to use the RMAN to back up and restore Oracle Database files to and from tape. Oracle Secure Backup supports nearly all tape drives and tape libraries in Storage Area Network (SAN) and Small Computer System Interface (SCSI) environments.

Oracle Secure Backup provides the ability to perform automatic tape drive cleaning as well as the option to manually clean a tape drive. The following article provides a brief overview of the tape cleaning functionality built into OSB.

Cleaning a Tape Drive using Oracle Secure Backup

Expect more article in the near future on the topic of Oracle Secure Backup. Namely installation and configuration steps in OSB as well as implementing RMAN backup and recovery strategies using the SBT interface of OSB.

iSCSI technology continues to gain strength in the database community. With its low entry cost, simple configuration, and rapidly growing support, many organizations are seeking to take advantage of their high-speed IP backbone over that of a Fibre Channel (FC) network.

To gain a better understanding of how an Oracle database server can make use of an iSCSI target for storage, I put together a brief introduction on how to install and configure an iSCSI Target and an iSCSI Initiator on the Solaris platform.

The iSCSI Initiator software is a built-in package included with the Solaris 10 Operating System. This article will also include instructions on how to configure an iSCSI Target using Openfiler.

The article can be found at:

http://www.idevelopment.info/data/Unix/Solaris/SOLARIS_ConnectingToAniSCSITargetWithOpen-iSCSIInitiatorUsingSolaris.shtml

iSCSI technology continues to gain strength in the database community. With its low entry cost, simple configuration, and rapidly growing support, many organizations are seeking to take advantage of their high-speed IP backbone over that of a Fibre Channel (FC) network.

To gain a better understanding of how an Oracle database server can make use of an iSCSI target for storage, I put together a brief introduction on how to install and configure an iSCSI Target and an iSCSI Initiator (Open-iSCSI) on the Linux platform.

The Linux Open-iSCSI Initiator is a built-in package included with Red Hat Enterprise Linux 5 or later. This article will also include instructions on how to configure an iSCSI Target using Openfiler.

The article can be found at:

http://www.idevelopment.info/data/Unix/Linux/LINUX_ConnectingToAniSCSITargetWithOpen-iSCSIInitiatorUsingLinux.shtml

Within the next several weeks, I will also publish this same article for configuring the iSCSI Initiator on the Solaris platform.

DBA's rely on Oracle's data dictionary views and dynamic performance views in order to support and better manage their databases. Although these views provide a simple and easy mechanism to query critical information regarding the database, it helps to have a collection of accurate and readily available SQL scripts to query these views.

Over the years, I have published a vast array of Oracle DBA scripts that can be used to manage many aspects of the database including space management, performance, backups, security, and session management. Once the scripts have been put in place, they can be easily run from within SQL*Plus while logged in as a DBA user.

The following article provides a new approach to SQL scripting that allows the Oracle DBA to collect a wide array of metrics and statistics using a single script. This "Snapshot Database" script will contain a collection of useful queries that run as a whole and produce an eye-catching HTML report. The report will contain critical database information including installed options, storage, performance data, and security.

The featured "Snapshot Database" article is available at:

http://www.idevelopment.info/data/Oracle/DBA_tips/Database_Administration/DBA_50.shtml

Currently, I have three separate Snapshot Database scripts available for each major Oracle release (8i, 9i, and 10g). The release for Oracle Database 11g will be released soon.

Although not as exciting as building an Oracle RAC or adding a new node and instance to a clustered database; removing a node from a clustered environment is just as important to understand for a DBA managing Oracle RAC 10g. While it is true that most of the attention in a clustered database environment is focused on extending the database tier to support increased demand, the exact opposite is just as likely to be encountered where the DBA needs to remove a node from an existing RAC environment. It may be that a server is being underutilized in the database cluster and could be better served in another business unit. Another scenario is a node failure. In this case, a node can be removed from the cluster while the remaining nodes continue to service ongoing requests.

I recently published an extension to two of my articles:

"Building an Inexpensive Oracle RAC 10g Release 2 on Linux - (CentOS 4.5 / iSCSI)"

and

"Adding a Node to an Oracle RAC 10g Release 2 Cluster on Linux - (CentOS 4.5 / iSCSI)".

Contained in this new article are the steps required to remove a single node from an already running and configured three-node Oracle RAC 10g Release 2 environment on the CentOS 32-bit (x86) platform. The node being removed is the third node I added in the second article. Although this article was written and tested on CentOS 4.5 Linux, it should work unchanged with Red Hat Enterprise Linux 4 Update 5.

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.

I recently published 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.

By default, the Oracle Database Configuration Assistant (DBCA) does not configure the TNS listener to accept client requests to an ASM instance running from a different node. Access will be denied for clients like SQL*Plus, Perl DBI:DBD, and JDBC when attempting to connect to an ASM instance from a node other than the node running the ASM instance. When the service is created for an ASM instance, its status is BLOCKED:

[oracle@linux1 ~]$ lsnrctl status LISTENER_LINUX1 | grep ASM
Service "+ASM" has 1 instance(s).
  Instance "+ASM1", status BLOCKED, has 1 handler(s) for this service...
Service "+ASM_XPT" has 1 instance(s).
  Instance "+ASM1", status BLOCKED, has 1 handler(s) for this service...

This limitation puts restrictions on scripts and other client tools that want to monitor and manage an ASM instance from a different node. Getting around this restriction, however, is an easy task that involves manually creating a service name for the ASM instance.

This article presents the steps required to access an ASM instance through the TNS listener from a client desktop. The database used in this article is a two-node Oracle RAC 10g clustered database where in fact there will two ASM instances (one ASM instance for each Oracle instance in the cluster). The database version is Oracle 10g Release 2 (10.2.0.3.0) running on CentOS 4.5 (or RHEL 4.5).

Comprehensive article on installing Oracle Database 11g Release 1 on Linux - (CentOS 5.1). This article should also work unchanged with the latest Red Hat Enterprise Linux 5.1.

Included in the article are detailed instructions for installing and configuring the Linux operating system to host the Oracle Database 11g Release 1 software and database. I also incorporated many tips that go beyond just simply installing the software to help newcomers to Oracle Database 11g better manage their database environment.

Comprehensive article on installing Oracle Database 10g Release 2 on Linux - (CentOS 5.1). This article should also work unchanged with the latest Red Hat Enterprise Linux 5.1.

Included in the article are detailed instructions for installing and configuring the Linux operating system to host the Oracle Database 10g Release 2 software and database. I also incorporated many tips that go beyond just simply installing the software to help newcomers to Oracle Database 10g better manage their database environment.

Learn how to configure an inexpensive Oracle RAC 11g environment on Linux using iSCSI technologies from Openfiler.

(For educational purposes only!)

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Learn how to configure an inexpensive Oracle10g RAC environment using VMware Workstation 5.5.3 and Red Hat 4 Update 4.

(For educational purposes only!)

Written by Dominic Giles, Swingbench is a free load generator (and benchmarks) designed to stress test an Oracle database (9i or 10g)

SwingBench consists of a load generator, a coordinator and a cluster \ overview. The software enables a load to be generated and the transactions/response times to be charted.

The essential step-by-step Oracle10g new features course for experienced Developers and Database Administrators.

This course book presents - in a succinct and practical fashion - an introduction to more than 120 new features introduced with Oracle Database 10g.

Release 1 and Release 2 features are covered.

Learn how to configure an inexpensive Oracle RAC 10g environment on Linux using iSCSI technologies from Openfiler.

(For educational purposes only!)

Learn how to configure an inexpensive Oracle10g RAC environment using FireWire 800 for shared storage.

(For educational purposes only!)