HP Serviceguard Enterprise Cluster Master Toolkit User Guide, December 2012 (5900-2145)

ASM File Descriptor Release
When an ASM disk group is dismounted on a node in the Serviceguard cluster, the ASM instance
closes the related descriptors of files opened on the raw volumes underlying the members of that
ASM disk group. x
Consider a configuration in which there are multiple databases using ASM to manage their storage
in a Serviceguard cluster. Assume each database stores its data in its own exclusive set of ASM
disk groups. If the database instance is shutdown on a node and then its ASM disk groups are
dismounted on that node, some ASM background and client processes may still hold open file
descriptors to the underlying raw logical volumes. Hence, an attempt to deactivate the corresponding
LVM volume group(s) on the node may fail.
Oracle has provided interim patches with which the ASM background processes close the file
descriptors on the dismounted disk group volumes.
However, any client connections into the ASM instance using sqlplus or Oracle Enterprise Manager
(OEM) results in ASM foreground processes opening file descriptors on all the disk group volumes
of all the database instances. These descriptors may not close on dismount of the disk group.
Oracle allows for terminating these foreground processes.
The toolkit package parameter KILL_ASM_FOREGROUNDS determines whether the scripts should
kill the ASM foregrounds if the file descriptors are open on the dismounted disk group volumes.
The ASM PMON process recovers foreground processes that were killed. This parameter can be
set either to yes or no only. The default value is “yes”.
The scripts will check whether ASM foreground processes of the form oracle <ASM_SID> have file
descriptors open on the dismounted disk group volumes of the database instance or not. If this
parameter is set to “yes”, and the ASM foregrounds have file descriptors open after dismount of
the disk group, the scripts remove them using a SIGTERM signal. Before removing the ASM
foreground processes, the scripts check every 3 seconds for a maximum of 12 seconds find out
whether the foreground processes have closed the file descriptors or not. If the file descriptors are
closed within this 12 second timeout, volume groups are deactivated without waiting for the
completion of this timeout. If this parameter is set to “no”, the ASM foregrounds are not killed.
However, when this parameter is set to “no”, and the file descriptors of ASM foregrounds are
open, volume group deactivation fail, therefore the database instance package halt will also fail.
Installing, Configuring, and Troubleshooting
Oracle ASM is part of the Oracle database server installation and does not require additional
software from HP to operate in the Serviceguard environment.
Oracle 11gR2 onwards, the Oracle Clusterware software must be installed to use Oracle ASM.
Oracle ASM and ASM disk groups may be configured before or while creating a database. Ensure
that the LVM volume groups and raw disks are prepared and activated before ASM disk group
configuration or reconfiguration. Use the names of raw LVs contained in the LVM volume groups
when configuring ASM disk groups. Ensure that each database instance uses different disk groups.
By default, Oracle 11gR2 onwards, the spfile of the ASM instance is stored on the ASM diskgroup.
This is true only for the ASM instance and not for the database instance that uses the ASM diskgroup.
For an ASM instance, the ECM Toolkit cannot verify the existence of the spfile on the ASM diskgroup.
So, it is mandatory that a pfile is created from the spfile on the local disk, at a location that ECMT
can access. The value of the pfile attribute of the ASM instance package must point to the pfile
that is created on the local disk.
Assume that the Serviceguard cluster, ASM instance, and one or more database instances are
already installed and configured.
• Halt the ASM and database instances.
• Configure the ASM MNP using the ECMT Oracle scripts. You must follow HP instructions in
the READ me file.
38 Using the Oracle Toolkit in an HP Serviceguard Cluster