HP XP Cluster Extension Software Administrator Guide

HP XP Cluster Extension reports a data center error. Depending on the cluster
software, the application service cannot start on any system in the local data center,
and the cluster software transfers the application service back to the remote data
center. Use this value to provide the highest level of application service availability.
Depending on the value configured for the AutoRecover object, HP XP Cluster
Extension attempts to update the former primary disk based on the secondary disk
and swaps the personalities of the disk pair so that the local disk will become the
primary disk.
In a two-node cluster, this process does not work because the target failback system
is not available. In this case, the application service must be started manually, or
the ApplicationStartup object must be set to RESYNCWAIT.
In an HP XP Cluster Extension for MSFC integration, HP XP Cluster Extension can
detect when there is no target failback system available in the remote data center.
In this case, HP XP Cluster Extension behaves as if the ApplicationStartup resource
property is set to RESYNCWAIT.
RESYNCWAIT
The online local cluster group must wait until the disk status is PAIR. HP XP Cluster
Extension initiates a resynchronization of the local disk based on the remote disk.
The copy process is monitored; if no copy progress is made after a monitoring
interval expires, the copy process is considered failed and HP XP Cluster Extension
returns a global error. If RESYNCWAIT has been specified for the ApplicationStartup
object, the ResyncWaitTimeout object must be specified, in case HP XP Cluster
Extension should wait for resynchronization changes for more or less than 90
seconds, which is the default.
AsyncTakeoverTimeout
Format Integer
Description (Optional) Specifies the horctakeover command timeout in seconds. Must be
adjusted based on disk mirroring link speed.
This object is used only if the FenceLevel object value is ASYNC.
The takeover operation for fence level ASYNC (Continuous Access) offers the option
to stop the data transfer process after a specified time value. This is used to allow
access to the remote copy if the data transfer process is stopped due to a Continuous
Access link failure. All data that has been copied up to the moment the timeout value
is reached is consistent and available to access at the secondary site.
CAUTION: Measure or calculate the full disk array cache copy time to use the
gathered information for the AsyncTakeoverTimeout object. After a takeover command
has been invoked, the Continuous Access software copies the side file area residing
in the disk array cache to the site where the takeover command has been issued
(the secondary disks). The side file area cannot exceed the installed cache size. The
maximum time for the AsyncTakeoverTimeout object is the time to fully copy the
amount of cache size data. The takeover timeout value is used to terminate the copy
process to provide access to the secondary disks; for example, if all links or the
primary disk array are unavailable to copy the side file area. The copy time depends
on the performance of the Continuous Access Software link between your sites. The
takeover or resynchronization operation could take longer than the timeout value
for application service startup in the cluster software. The application service startup
might fail in this case. However, the takeover or resynchronization command will
continue in the background.
APPLICATION objects 69