Using the Event Monitoring Service (June 2007)

Monitoring ServiceGuard Package Dependencies
Chapter 4 47
4 Monitoring ServiceGuard
Package Dependencies
This chapter describes how to use HP SMH 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
Refer to the MC/ServiceGuard User Guide for procedures on configuring
EMS resource dependencies.
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).