Using Serviceguard Extension for RAC Version A.11.20 - (August 2011)

or later) to support ASM on raw disks/disk array LUs. In HP-UX 11i v3, new DSF is introduced.
SGeRAC will support the DSF format that ASM support with the restriction that native multipathing
feature is enabled.
The advantages for “ASM-over-raw” are as follows:
• There is a small performance improvement from one less layer of volume management.
• Online disk management (adding disks, deleting disks) is supported with ASM-over-raw.
The disadvantages for “ASM-over-raw” are as follows:
• Might not see the HP-UX devices (raw disks/disk array LUs) used for disk group members as
the same names on all nodes.
• There is no protection to prevent the raw disks from being incorporated into VxVM volume/disk
groups.
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 the following:
For Oracle 10g R2, please refer to Oracle Database Installation Guide 10g Release
2 for hpux 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
This section includes some pointers that may be useful when deploying ASM in an SGeRAC
environment.
Consider using the MNP/Simple Dependency-based SGeRAC Toolkit’s Framework
The SGeRAC Toolkit 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 an 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
Additional Hints on ASM Integration with SGeRAC 77