Presentation (To Host); Remote Replication Guidelines - HP 418800-B21 - StorageWorks Modular Smart Array 70 Storage Enclosure User Manual

• No preference. Presentation of the virtual disk is completely controlled by the controller software.
• Path A - Failover only. Controller A presents the virtual disk to hosts when both controllers are
simultaneously started.
• Path A - Failover/failback. Controller A presents the virtual disk to hosts, but if controller A
fails, control of the virtual disk is transferred to controller B, then transferred back to controller A
when it is available again.
• Path B - Failover only. Controller B presents the virtual disk to hosts when both controllers are
simultaneously started.
• 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
• Source and destination arrays must have remote replication licenses. See
replication licenses
• The array selected for the destination DR group depends on the remote replication configuration.
For supported configurations, see the HP StorageWorks Continuous Access EVA planning guide.
• A storage array can have DR group relationships with up to two other storage arrays.
• 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
DR groups and failover
• Failover of a DR group pair is permitted only by specifying a destination DR group.
• When failsafe on unavailable member is enabled, a DR group pair cannot be suspended. See
failsafe on unavailable
• When a DR group pair is suspended, it cannot be failed over or reverted to home.
• A DR group cannot be deleted if a virtual disk in the destination DR group is presented.
• For additional help on usage, see
Virtual disks
• All virtual disks that contain the data for an application must be in the same DR group.
• 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
• When suspended, virtual disks cannot be removed from the source or destination DR group.
• Virtual disks cannot be directly added to a destination DR group.
• To be added to a source DR group, a virtual disk:
• Cannot be a member of another DR group
overview.
member, suspend on
using DR
HP StorageWorks Replication Solutions Manager 4.0.1
controller software features - remote
failover.
groups.
replication.
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