Using the Event Monitoring Service (November 1999)

Chapter 5 55
Monitoring ServiceGuard Package Dependencies
5 Monitoring ServiceGuard
Package Dependencies
This chapter describes how to use SAM to define package dependencies
on EMS resources. ServiceGuard by itself automatically monitors
specific resources. Using ServiceGuard with EMS adds to the list of
resources that can be monitored. These resources need to be configured
and identified to ServiceGuard as package resource dependencies.
You create a monitoring request to observe the EMS resource and to
notify ServiceGuard when that resource reaches a critical user-defined
level. At that time ServiceGuard will fail over the package. The following
are some examples of how EMS might be used:
• In a cluster where one copy of data is shared between two nodes (both
configured with EMS), you may want to fail a package over when, for
example, the LAN or SCSI host adapter fails on the node running the
package. ServiceGuard compares the resource UP values on other
configured nodes, and fails the package over to the node that has the
correct resources available.
• In a cluster where each node has its own copy of data, you may want
to failover a package to another node for any number of reasons:
— host adapter, bus, controller, or disk failure
— unprotected data (the number of copies is reduced to one)
— degraded performance because one of the PV links has failed
This information for creating requests is also valid for EMS sold with
other products (ATM, OTS, HyperFabric, or STM hardware monitors, for
example) and for user-written monitors written according to developer
specifications in Writing Monitors for the Event Monitoring Service
(EMS) (HP Part Number B7611-90016).
NOTE Create the same requests on all nodes configured for an ServiceGuard
package.