DBA Tips Archive for Oracle
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by Michael New, MichaelNew@earthlink.net, Gradation LLC
This guide provides the steps to create and configure blank files (instead of real disk devices) for use in testing Oracle's Automatic Storage Manager (Oracle ASM) on the Windows platform. This is a handy trick that can be used when the DBA needs to test Oracle ASM on a machine that has no free disk partitions or no free disk devices available.
The first step is to identify an already partitioned and formatted hard disk that contains enough space to store the blank files to be used as ASM disk devices.
A total of four (4) files at 100MB each will be created on the local hard disk (C:\). A single disk group will be created containing the four disks. The disk group will contain two failure groups and each failure group will be created using two disks.
From within the Windows O/S platform, perform the following actions.
An Oracle ASM instance is already running on the node named +ASM. Set the following initialization parameters for the ASM instance to allow ASM to use a device rather than a RAW / Logical disk (a blank text file for this example) and to discover from a non-default location.
Bounce the Oracle ASM instance.
Create a new directory for device files.
Now the cool part, to make four 100MB text files using Perl which will act as device files for Oracle ASM. You can use the Perl binary that came installed with Oracle or download ActivePerl.
Now, run the Perl script using your favorite Perl interpreter.
For the purpose of this example, an Oracle ASM instance is already running on the node named +ASM.
With the new device files in place and seen by the O/S, discover these disks within Oracle ASM and then create the disk group.
Start by determining if Oracle can find the four new disks. The view V$ASM_DISK can be queried from the ASM instance to determine which disks are being used or may potentially be used as ASM disks. Note that you must log into the Oracle ASM instance with SYSDBA privileges. Run the following query from the Oracle ASM instance as SYSDBA.
Note the value of zero in the GROUP_NUMBER column for all four disks. This indicates that a disk is available but hasn't yet been assigned to a disk group.
Create a disk group with normal redundancy and two failure groups.
Validate the new disk group and disk details.
Jeffrey Hunter is an Oracle Certified Professional, Java Development Certified Professional, Author, and an Oracle ACE. Jeff currently works as a Senior Database Administrator for The DBA Zone, Inc. located in Pittsburgh, Pennsylvania. His work includes advanced performance tuning, Java and PL/SQL programming, developing high availability solutions, capacity planning, database security, and physical / logical database design in a UNIX / Linux server environment. Jeff's other interests include mathematical encryption theory, tutoring advanced mathematics, programming language processors (compilers and interpreters) in Java and C, LDAP, writing web-based database administration tools, and of course Linux. He has been a Sr. Database Administrator and Software Engineer for over 20 years and maintains his own website site at: http://www.iDevelopment.info. Jeff graduated from Stanislaus State University in Turlock, California, with a Bachelor's degree in Computer Science and Mathematics.
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Last modified on
Thursday, 19-Jan-2012 01:13:43 EST
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