Designing Disaster Tolerant High Availability Clusters, 10th Edition, March 2003 (B7660-90013)

Building a Metropolitan Cluster Using MetroCluster/CA
XP/CA Device Group Monitor
Chapter 3116
XP/CA Device Group Monitor
In the MetroCluster/CA environment where the device group state is not
actively monitored and the end user may not be aware when the
application data is not remotely protected for an extended period of time.
Under these circumstances, the XP/CA device group monitor provides
the capability to monitor the status of the XP/CA device group that is
used in a package. The XP/CA device group monitor, based on a
pre-configured environment variable, also provides the ability to perform
automatic resynchonization of the XP/CA device group upon link
recovery.
NOTE If the monitor is configured to automatically resynchronize the data from
PVOL to SVOL upon link recovery, a Business Copy (BC) volume of the
SVOL should be configured as another mirror.
In the case of a rolling disaster and the data in the SVOL becomes
corrupt due to an incomplete resychronization, the data in the BC
volume can be restored to the SVOL. This will result non-current, bust
usable data in the BC volumes
The monitor, as a package service, periodically checks the status of the
XP/CA device group that is configured for the package, and sends
notification to the user via email, syslog, and console if there is a change
in the status of the package’s device group.