HP P6000 Continuous Access Software - Manual (Page 92)

◦ Must use mirrored cache, see virtual disks Cache policies
◦ Must have the same presentation status as other virtual disks in the DR group. With some
versions of controller software, the virtual disk must be presented to a host. See storage
systems
Controller software features - remote replication . See also virtual disks Presentation .
Suspend on failover
Suspend on failover is an event that combines the failover of a DR group pair and suspension of
remote replication. The DR group pair is failed over, followed immediately by suspension of remote
replication. See DR groups
Suspension state and Remote replication guidelines .
This event can be initiated through the replication manager GUI, jobs, or the CLUI. See DR groups
Actions cross reference .
IMPORTANT: Do not initiate this event when the remote replication links are down, especially
during an unplanned failover. Doing so can create an invalid source-source configuration. See
Invalid DR group pair - source and source .
IMPORTANT: Do not initiate this event if the failsafe mode of the DR group pair is enabled. This
can create an invalid configuration.
Controller software versions
Implementation of this feature is controller software dependent. See Controller software features -
remote replication .
Suspension state
Suspension state
Suspension state indicates if remote replication in a DR group pair is allowed or has been stopped.
Values are:
•
Suspended. Remote replication in the DR group pair has been stopped.
•
Resumed. Remote replication in the DR group pair is allowed.
IMPORTANT: You cannot remove virtual disks from a DR group pair when remote replication is
suspended.
Write mode (async/sync replication)
The replication write mode of each DR group pair can be asynchronous or synchronous. The choice
is typically a business decision based on your goals and the bandwidth of the intersite link. Unless
specified otherwise, replication write mode is set to synchronous when you create a DR group
pair.
Write mode comparison (summary)
Synchronous Best data protection
Asynchronous Best host I/O performance
Asynchronous write mode
In asynchronous write mode, the source array acknowledges host writes before the data is replicated
on the destination array. This process allows faster host I/O than with synchronous. From a data
protection standpoint, there can be brief instances in which the data is not identical on the source
and destination DR group.
92 DR groups