Support of Oracle RAC ASM with SGeRAC, January 2008

HP Availability Clusters Solutions Lab 1/25/2008 Page 16
Configure Raw Disks/Disk Array Logical Units for ASM Disk Group
Oracle provides instructions on how to configure disks for ASM where the member disks are raw
logical volume. The instructions to configure raw disks/disk LUs are:
For Oracle 10g R2, please refer to Oracle Database Installation Guide 10g Release 2 for hp-
ux Itanium , Chapter 2, Preinstallation Tasks, section “Preparing Disk Group for an Automatic
Storage Management Installation”.
For 11g R1, please refers to Oracle Clusterware Installation Guide 11g Release 1 (11.) for
HP-UX, Chapter 5, Configuring Oracle Real Application Clusters Storage, section
“Configuring Disks for Automatic Storage Management”.
Then, these raw devices can be used as disk group members to configure ASM disk group members
using Oracle database management utilities.
Additional Hints on ASM Integration with SGeRAC
In this section, we provide some pointers that may be useful when deploying ASM in a SGeRAC
environment.
Consider using the MNP/Simple Dependency-based SGeRAC Toolkit’s
Framework
The SGeRAC Toolkit
3
which provides a framework to integrate Oracle 10g R2 RAC or 11g R1 RAC
with SGeRAC and is based on the SGeRAC A.11.17 multi-node package and simple package
dependency features provides a uniform, intuitive and easy-to-manage method to co-ordinate between
SGeRAC and Oracle Clusterware and manage all the storage options supported by SGeRAC,
including ASM-over-SLVM and ASM-over-raw devices.
ASM Halt is needed to ensure disconnect of ASM from SLVM Volume
Groups
This section is specific to ASM-over-SLVM only.
When an ASM disk group is dismounted on a node in the SGeRAC cluster, there is no guarantee that
processes in the ASM instance on that node and client processes of the ASM instance will close their
open file descriptors for the raw volumes underlying the members of that ASM disk group.
Consider a configuration in which there are multiple RAC databases using ASM to manage their
storage in a SGeRAC cluster. Assume each database stores its data in its own exclusive set of ASM
disk groups.
If we shut down the database instance for a specific RAC database on a node, and then dismount its
ASM disk groups on that node, some Oracle processes may still hold open file descriptors to the
underlying raw logical volumes. Hence an attempt at this point to deactivate the corresponding SLVM
volume group(s) on the node may fail. The only way to ensure success of the deactivation of the
volume groups is to first shut down the ASM instance and its clients (including all databases that use
ASM based storage) on that node.
The major implications of this behavior include the following: