HP 3PAR Operating System Software - Manual (Page 149)

Figure 60 No Communication among Quorum Witness, Site 1, and Site 2
When all communication fails, service to the host must be manually re-enabled by transitioning the
volumes groups out of the failsafe state on the primary storage SystemA, thus exporting the
associated volumes to the attached hosts. From the command line, this is done by issuing the
setrcopygroup
override subcommand on a group or list of remote-copy replication groups.
To re-establish service to the host, issue the following command:
# setrcopygroup <dr_operation> [options] [<pattern>] [<target_name | group_name>...]
Path Management Policies
The purpose of the path_management policy is to allow peer-persistent remote copy groups to
be configured to support ESX uniform host access.
With uniform host access, each host can access the storage resources on both storage systems.
With source and target replication volumes exported and accessible to the host, it is necessary to
control access such that host I/O is directed to the source replication volumes only. To control
access, the ALUA state of peer-persistence source volumes in groups for which the
path_management
policy is enabled is set to ACTIVE, and the ALUA state of the corresponding
target volumes is set to STANDBY.
If the storage on one site should fail (for example, through failover, restoration, recovery, or
switchover), then the storage fails over to the other site transparently, and the I/O is redirected—the
target volumes are transitioned to become the new source replication volumes, and the ALUA state
of these exported volumes changes to ACTIVE to allow host access.
If path_management is not enabled, the ALUA state of all exported volumes is set to ACTIVE.
Both source and target replication volumes are accessible to the host cluster, and host access must
be controlled at the host level.
Should an ESX host become disconnected from the primary volumes and be able to see only
secondary volumes (that is, have non-uniform volume access), it may be necessary either to disable
the path_management policy for those volume groups until the uniform cluster is re-established
or, on the secondary cluster, to change the ESX host persona to 6.
For information about enabling and disabling policies, see “Setting Volume Group Policies” (page
118) .
The response of volumes in the STANDBY state to the SCSI Test Unit Ready with Check Conditions
will depend on the host persona in effect.
Path Management Policies 149