HPP Enterprises P4000 SAN - Manual (Page 36)

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From XenCenter, you can discover multiple XenServer hosts that are similarly configured with
resources.
Configuring VMs for high availability
You can use XenServer’s High Availability (HA) feature to enhance the availability of a XenServer
resource pool. When this option is enabled, XenServer continuously monitors the health of all hosts in
a resource pool; in the event of a host failure, specified VMs would automatically be moved to a
healthy host.
In order to detect the failure of a host, XenServer uses multiple heartbeat-detection mechanisms
through shared storage as well as network interfaces.
Note
It is a best practice to create bonded interfaces in HA configurations to
maximize host resiliency, thereby preventing false positives of component
failures.
You can enable and configure HA using the Configure HA wizard.
Creating a heartbeat volume
Since XenServer HA requires a heartbeat mechanism within the SR, you should create a special HP
StorageWorks iSCSI volume for this purpose. This heartbeat volume must be accessible to all
members of the resource pool and must have a minimum size of 356MB.
It is a best practice to name the heartbeat volume after the resource pool, adding “HeartBeat” for
clarity. Thus, in this example, resource pool HP_Boulder-IT includes a 356MB iSCSI volume named
HP-Boulder-IT-HeartBeat that can be accessed by both hosts, XenServer-55b-01 and XenServer-55b-
02, as shown in Figure 29.
Figure 29. A volume named HP-Boulder-IT-HeartBeat has been added to the resource pool
You can now use XenCenter to create a new SR for the heartbeat volume. For consistency, name the
SR HP_Boulder-IT-HeartBeat.
As shown in Figure 30, the volume appears in XenCenter with 356MB of available space; 4MB is
used for the heartbeat and 256MB for pool master metadata.