Silicon Graphics InfiniteStorage 4000 Series, Настройка и обслуживание

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138 Canceling a Pending Asynchronous Mirror Group Role Change
If the role change is interrupted because of a communication failure between the
storage arrays, the mirror roles can possibly end as two secondary roles. This role
conflict does not compromise the data synchronization state.
Canceling a
Pending
Asynchronous
Mirror Group
Role Change You can cancel a pending role change by running this command:
stop asyncMirrorGroup rolechange
This command restores the asynchronous mirror group to the normal operating state
including write requests to the volumes on the primary volume. The synchronization
process that was started as part of the role change operation is allowed to finish. The
next periodic resynchronization is scheduled based on the most recently completed
periodic synchronization and the current asynchronous mirror group synchronization
settings.
Resolving Role
Conflicts Because you can force a change in the role of the storage arrays in an asynchronous
mirror group, sometimes this might result in a condition where you have two primary
or two secondary roles at the same time. This usually occurs when communications
between the storage arrays cannot take place. For example, the original primary side
might be operational, but cannot be reached because of a link failure. In this case, a
forced promotion of the secondary to become a primary results in both sides being
able to receive new data write requests since the most recent resynchronization. Later,
the original primary site might be reactivated or connectivity reestablished resulting
in both local and remote storage arrays viewing themselves as the primary.
If you have a role conflict, your asynchronous mirror group might have two primary
volumes or two secondary volumes in an asynchronous mirror group. If you have two
primary volumes, both volumes can accept host writes, but you do not have any
mirror volumes. If you have two secondary volumes, neither volume can accept host
writes. In either case you no longer have a valid asynchronous mirror group.
If such a role conflict occurs, you need to transition the mirrored pair back to a state in
which one side is clearly recognized as primary and the other as secondary. To
transition back to a valid asynchronous mirror group, use this command.
set asyncMirrorGroup [" asyncMirrorGroupName "]
role=(primary | secondary)
Run this command on one of the storage arrays in the asynchronous mirror group and
define the role of that storage array as you need to meet your mirroring requirements.
Define the storage array as either the storage array with the primary volumes or the
storage array with the secondary volumes.