HP XP Cluster Extension Software Administrator Guide

Creating RAID Manager command devices
To control Continuous Access mirrored disks from a clustered server, install RAID Manager on the
server and configure a special disk, called a command device. The command device must not be
an MSFC 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.
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 RAID Manager documentation for more information.
Configuring RAID Manager command devices
In-band and out-of-band communication
Previous versions of XP Cluster Extension used in-band communication through the FC link to
communicate with XP arrays. XP Cluster Extension supports in-band communication through the FC
link and out-of-band communication through the IP link. Out-of-band communication is supported
only with XP arrays and XP RAID Manager.
When out-of-band communication is used, XP Cluster Extension must be configured to use command
device authentication.
When in-band communication is used, command device authentication must be configured only
if the command device user authentication property is enabled. No authentication credentials are
required if the user authentication property is disabled.
When command device authentication is configured, XP Cluster Extension logs in to a command
device in order to perform RAID Manager replication and provisioning commands.
Command device authentication
XP Cluster Extension supports command device user authentication for physical and virtual command
devices on XP disk arrays. When you enable command device user authentication, you must add
the command device credentials to XP Cluster Extension as part of the XP Cluster Extension
configuration procedure.
NOTE: HP recommends using the same user name and password for all command devices
configured in a single HORCM file. For more information, see the RAID Manager documentation.
Creating RAID Manager instances
XP Cluster Extension requires at least one instance of RAID Manager. XP Cluster Extension starts
the configured RAID Manager instance if it is not running. However, if the RAID Manager instance
cannot be started or returns an error, XP Cluster Extension can switch to an alternate RAID Manager
instance.
• Ensure that the path to the RAID Manager binary files is included in the PATH environment
variable.
• Create a 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 RAID Manager
instances to provide redundancy. Bear in mind, however, that the RAID Manager instance
numbers used for the RaidManagerInstances object must be the same among all servers using
XP Cluster Extension.
• HP recommends that the RAID Manager instances be running at all times to provide the fastest
failover capability. XP Cluster Extension provides scripts to include the RAID Manager startup
procedure in the system startup file . See “Starting and stopping the RAID Manager instances”
(page 11) for more information. XP Cluster Extension starts the configured RAID Manager
instances if it cannot find any running instance.
10 XP Cluster Extension features