HP XP7 Storage - Manual (Page 149)

Figure 48 Server failover system configuration
Legend
•
CM (Cluster Manager) : Demon process that keeps the consistency of the cluster by monitoring
the node and server program in the cluster.
•
Script : Shell script that automatically performs takeover process when CM detects the server
failure.
In an HA environment, a package is a group of applications that are scripted to run on the
secondary host in the event of a primary host failure. When using the HA software (for example,
MC/ServiceGuard), the package can be transferred to the standby node as an operation executed
by the system administrator (see
Figure 49 (page 149) ).
NOTE: If the operation is performed when RAID Manager and Continuous Access Synchronous
are being used, the volume is switched from primary to secondary as if an error had occurred,
even though data consistency is assured. When restoral of the original node occurs along with its
original package (group of applications), it is necessary to copy the data on the secondary volume
onto the primary volume; this operation can take as much time as the initial copy operation for the
pair. In actual operation, no package can be transferred when Continuous Access Synchronous
is being used. The secondary package is switched to the primary package, and vice versa, when
the primary volume is switched to the secondary volume. Therefore, the primary and secondary
Continuous Access Synchronous volumes should be switched depending on the package state.
Figure 49 Package transfer on high availability (HA) software
Continuous Access Synchronous operations 149