HP P6000 Cluster Extension Software Administrator Guide (5697-2274, November 2012)

P6000 Cluster Extension resources (MSCS) return a data center error and fail the resource if the
DR group status indicates that the problem experienced locally would not be solved on another
system connected to the same P6000/EVA storage system. This means that all systems specified
in the DC_A_Hosts resource property or the DC_B_Hosts resource property would fail to bring the
application online.
Depending on the application and the resource property values, the resource tries to start on
different nodes several times. If the remote data center is down, this looks like the application
alternates (bounces) between the surviving systems. This happens until the application property
values are reached or until the user disables the restart of the resource.
This could be also the case if the ApplicationStartup resource property has been set to
FASTFAILBACK.
If a DR group state is discovered that does not allow bringing the application/package on any
system in the cluster, a cluster error is reported and the resource fails on all systems. This could
lead to the same behavior as described for a P6000 Cluster Extension data center error.
In any case, HP does not recommend restarting a failed application/package without investigating
the problem. A failed P6000 Cluster Extension resource indicates the need to check the status of
the DR group and its member vdisks and decide whether it is safe to continue or not.
All cluster nodes must to be able to communicate with the management server
All cluster nodes must be able to communicate with the management server that hosts the HP
P6000/EVA SMI-S server.
If there a communication error message during the initialization phase in the P6000 Cluster
Extension log file, verify that the HP P6000/EVA SMI-S server can look up the cluster node names
correctly and connect to the cluster nodes. Use nslookup and ping to do this. You can also use
the hosts file to add cluster host names for name resolution to make sure that the HP SMI-S server
can resolve names.
If there is a communication error message during the initialization phase in the P6000 Cluster
Extension log file, use nslookup and ping to check if the node is able to look up the HP
P6000/EVA SMI-S server correctly and can connect to it. You can also use the hosts file to add
cluster host names for name resolution to ensure that the cluster node can resolve other system
names.
This applies to all cluster nodes.
Failing physical disk resources during online attempt of the resource group
When resource groups that use P6000 Cluster Extension for DR group failover are brought online,
physical disk resources fail for two reasons:
• The physical disk resource does not have a dependency on its P6000 Cluster Extension
resources/packages configured. Review the setup steps for P6000 Cluster Extension resources.
• The DR group is created with access mode disabled and has not been set to read-only access
for the destination vdisk(s). The disk resource fails initially. After rescanning the disks in the
Device Manager (disk management), the physical disk resource goes online as expected.
However, the physical disk resource might fail again after a later server reboot. Setting the
destination vdisk access mode to read-only solves this issue.
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