HP StorageWorks XP Cluster Extension Software Administrator Guide (T1656-96035, April 2010)

system list (which should be a local system). This fails because the state of the local XP disk array has
not changed. The service group fails until the service group is brought online on a system connected
to the remote XP disk array. The service group online process takes longer and it does not access the
VCS configuration file.
Restrictions for VCS with XP Cluster Extension
The following restrictions apply for VERITAS Cluster Server configurations when XP Cluster Extension
is used to enable failover between two XP disk arrays:
• The XP Cluster Extension resource must be the first (child) resource for all other disk resources.
• Heartbeat disks cannot be used because of the P/S-VOL read/write behavior of XP Continuous
Access Software.
• No service group heartbeat disks are allowed in the service group. The ServiceGroupHB resource
is not supported in XP Cluster Extension configurations because of the P/S-VOL read/write beha-
vior of XP Continuous Access Software.
• Only one XP Cluster Extension resource is allowed to be configured per service group.
• XP Cluster Extension must not be used with parallel service groups. If XP Cluster Extension is used
in a parallel service group, all systems configured for this service group must be connected to the
same XP disk arrays. A failover operation to the secondary XP disk array must be done manually
only. In such a case, all active service groups must be brought offline before any of those service
groups can be brought online on the secondary XP disk array.
• The ApplicationDir attribute value must not be changed when the resource is online.
The ApplicationDir attribute defines the location of the application_dir/resource_name.on-
line file. This file is created when the resource is brought online (if ResyncMonitor attribute is set
to NO). The XP Cluster Extension resource monitors the file located in the location specified by
ApplicationDir. Changing this attribute can cause the XP Cluster Extension resource to fail.
• The resource online timeout must be greater than the value specified for the ResyncWaitTimeout
attribute.
• The resource online timeout should be greater than twice the wait time of all remote XP RAID
Manager instances times the number of remote systems. Otherwise, the XP Cluster Extension resource
fails to go online when there is a complete remote data center failure. If a post-executable is spe-
cified, the resource online timeout should be greater than the number of remote systems multiplied
by three times t
WT.
t
online
> n
remote systems
x 2 x t
WT
where:
t
online
= resource online timeout
n
remote systems
= number of remote systems configured to run XP RAID Manager instances
t
WT
= wait time until remote error will be reported by local XP RAID Manager instance
Unexpected offline conditions
In rare cases, XP Cluster Extension resources go offline after the following conditions all occur at the
same time:
• The cluster has been stopped forcibly (without taking the resources offline).
• The XP Continuous Access links have failed.
• A remote XP RAID Manager instance is not available due to a full network outage.
Configuring XP Cluster Extension for Solaris90