Continuous access synchronous remote commands – HP XP P9500 Storage User Manual
Page 139
Figure 48 Server failover system configuration
Legend
•
CM (Cluster Manager): Daemon 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
Package transfer on high availability (HA) software (page 139)
).
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 remote commands
Continuous Access Synchronous remote system configuration (page 140)
illustrates a Continuous
Access Synchronous remote configuration. The RAID Manager Continuous Access Synchronous
remote commands assist the system operation with volume backups among UNIX servers and their
operating system management functions. The Continuous Access Synchronous remote pair commands
Continuous Access Synchronous operations
139