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

Disk monitoring
For the situations in which disk access is lost or read/write protection is in effect due to storage fencing,
application monitoring agents, file system agents, or LVM resource agents detect the IO failure. XP
Cluster Extension does not monitor the disk access status.
Setting up XP RAID Manager
In addition to the cluster software it integrates with, XP Cluster Extension depends on HP StorageWorks
XP RAID Manager. Before configuring XP Cluster Extension, verify that XP RAID Manager is installed
and configured, and that the host and disk array systems are properly configured as described in the
following topics.
Creating XP RAID Manager command devices
To control XP Continuous Access Software mirrored disks from a clustered server, install XP RAID
Manager on the server and configure a special disk, called a command device. The command device
must not be an MSCS resource, cannot be paired, and is assigned to a 36 MB or greater CVS volume.
The command device is identified by CM appended to the emulation type.
XP RAID Manager command devices can be accessed by redundant paths. HP recommends redundant
paths to prevent XP Cluster Extension from aborting if one path to the command device is missing.
See the HP StorageWorks XP RAID Manager User's Guide for more information.
NOTE:
If you use Auto Path to enable alternate pathing on IBM AIX together with the XP disk array, XP RAID
Manager does not support Auto Path virtual paths for command devices.
Creating XP RAID Manager instances
XP Cluster Extension requires at least one instance of XP RAID Manager. XP Cluster Extension starts
the configured XP RAID Manager instance if it is not running. However, if the XP RAID Manager
instance cannot be started or returns an error, XP Cluster Extension can switch to an alternate XP RAID
Manager instance.
• Ensure that the path to the XP RAID Manager binary files is included in the PATH environment
variable.
• Create an XP RAID Manager instance to control pair operations and to gather disk array status
information. Because XP Cluster Extension switches to the next available instance when a current
instance becomes unavailable, HP recommends that you create several XP RAID Manager instances
to provide redundancy. Bear in mind, however, that the XP RAID Manager instance numbers used
for the RaidManagerInstances object must be the same among all servers using XP Cluster Extension.
• HP recommends that the XP RAID Manager instances be running at all times to provide the fastest
failover capability. XP Cluster Extension provides scripts to include the XP RAID Manager startup
procedure in the system startup file (for example, /etc/inittab for non-Windows systems). See
“Starting and stopping the XP RAID Manager instances” on page 22 for more information. XP
Cluster Extension starts the configured XP RAID Manager instances if it cannot find any running
instance.
XP Cluster Extension features20