HP P6000 Continuous Access Software - Manual (Page 268)

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Path B - Failover only. Controller B presents the virtual disk to hosts when both controllers are
simultaneously started.
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Path B - Failover/failback. Controller B presents the virtual disk to hosts, but if controller B
fails, control of the virtual disk is transferred to controller A, then transferred back to controller
B when it is available again.
Presentation (to host)
Presentation of a virtual disk to a host makes the virtual disk visible to the host and allows the host
to perform I/O with it. After a virtual disk is presented to an enabled host, the replication manager
can identify the presented virtual disk as a host volume.
CAUTION: Presenting a virtual disk to more than one host at a time, or multiple times to the same
host, can cause I/O write conflicts on the disk and the possible loss of host application data.
Remote replication guidelines
Storage arrays
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Source and destination arrays must have remote replication licenses. See Replication licenses
overview .
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The array selected for the destination DR group depends on the remote replication configuration.
For supported configurations, see the HP P6000 Continuous Access Implementation Guide.
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A storage array can have DR group relationships with up to two other storage arrays.
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The maximum number of virtual disks in a DR group and the maximum number of DR groups
per array vary with controller software versions. See
Controller software features - remote
replication .
DR groups and failover
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Failover of a DR group pair is permitted only by specifying a destination DR group.
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When failsafe on unavailable member is enabled, a DR group pair cannot be suspended.
See
Failsafe on unavailable member and Suspend on failover .
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When a DR group pair is suspended, it cannot be failed over or reverted to home.
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A DR group cannot be deleted if a virtual disk in the destination DR group is presented.
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For additional help on usage, see Using DR groups .
Virtual disks
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All virtual disks that contain the data for an application must be in the same DR group.
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When in enhanced asynchronous write mode, virtual disks cannot be added to or deleted
from a DR group. This restriction is controller software version dependent. See
Controller
software features - remote replication .
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When suspended, virtual disks cannot be removed from the source or destination DR group.
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Virtual disks cannot be directly added to a destination DR group.
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To be added to a source DR group, a virtual disk:
Cannot be a member of another DR group ◦
◦ Cannot be a snapshot or a mirrorclone. See virtual disks Types .
◦ Cannot have a mirrorclone. This restriction is controller software version dependent. See
Controller software features - remote replication .
268 Virtual disks