Using High Availability Monitors (June 2003)

Monitoring Disk Resources
Rules for Using the HA Disk Monitor with ServiceGuard
Chapter 2 37
Setting Failover Parameters
When using the HA Disk Monitor with ServiceGuard, the parameters
listed in Table 2-6 should be set so that a package failover will occur
when access to a disk resource fails.
Working with Physical Volume Groups
The pv_summary is calculated based on the compiled results of SCSI
inquiries to all physical volumes in a volume group. To help you
determine the best way to configure your disks for monitoring, here are
the assumptions made by the monitor when calculating pv_summary:
• PVGs (physical volume groups) are set up to be bus-specific sides of a
mirror or redundant links, PVGs have an equal number of physical
volumes.
• All logical volumes within a volume group are mirrored in the same
way: all 2-way or all 3-way mirroring.
• If you are configuring a monitoring request through ServiceGuard, a
package depends on all logical volumes in the volume group.
• The SCSI inquiry will retry on devices that are BUSY. BUSY devices
are not considered UP when calculating pv_summary.
These rules apply when creating a PVG. If the rules are not followed,
pv_summary will not be available for monitoring:
• If PVGs are used, all physical volumes in a volume group must be in
a PVG.
• All PVGs in a volume group must have the same number of physical
volumes.
Table 2-7 is a summary of how pv_summary is calculated where
Table 2-6 Setting Failover Parameters
Parameter Setting Notes
RUN_SCRIPT_
TIMEOUT
non-zero
timeout value
Do not leave these parameters
set to the default, NO_TIMEOUT.If
you do, the run or halt script
hangs the package and will not
proceed with its action.
HALT_SCRIPT_
TIMEOUT
non-zero
timeout value