HP EVA Cluster Extension Software Administrator Guide (5697-2445, July 2013)

requested status information is reported. This ensures the priority of data integrity over cluster
software failover behavior. However, in some cases, this behavior can cause a failure of the Cluster
Extension EVA resources.
• When EVA Cluster Extension uses HP EVA SMI-S to communicate with the HP EVA storage
system, depending on the settings of the SMI-S request timeout property and the number of
retries, the online operation could time out. This can occur if the list of management servers
is populated with many management servers and the EVA storage system is busy processing
other management commands.
• When a DR group member resynchronization (merge) is in progress, the software waits until
the DR group is in a normal state if the ApplicationStartup resource property is set to
RESYNCWAIT. In case of merge/resynchronization, the delta data (stored in the history log)
between the source and destination vdisks could be large enough for the copy process to
exceed the resource PendingTimeout value.
• The values of the ResyncWaitTimeout and DataSyncTimeout properties must be less than the
configured resource PendingTimeout value.
In general, because the failover environment is dispersed into two (or more) data centers, the
failover time cannot be expected to be the same as that in a single data center with a single shared
disk device. Therefore, the following Cluster Extension EVA resource values and the service or
application using that resource, must be adjusted, based on the failover tests performed to verify
the proper configuration setup:
• FailoverPeriod
• RestartPeriod
• PendingTimeout
• LookAlive
• IsAlive
In addition, the service or application's FailoverPeriod value must be higher than the resource's
RestartPeriod value and both must be higher than the resource's PendingTimeout value.
Microsoft Cluster Server provides two properties to adjust state change recognition/resolution:
• IsAlive
• LookAlive
The software automatically calls the IsAlive function whenever the cluster service calls the LookAlive
function. Therefore, both functions must be set to the same value.
NOTE: For Windows Server 2008/2008 R2/2012, the IsAlive and LookAlive properties are
replaced by the Thorough Resource Health Check Interval and Basic Resource Health Check Interval
properties.
Bouncing service or application
EVA Cluster Extension alternates (start and fail) between local nodes if the ApplicationStartup
property is set to FASTFAILBACK and no remote system is available until the service or application
restart limit has been reached. For more information, see “APPLICATION objects” (page 51).
Administration
EVA Cluster Extension administration includes remote management of resources and monitoring
of system resources and logs.
Bouncing service or application 43