HP P6000 Continuous Access Implementation Guide (T3680-96431, August 2012)

• Support for array-to-array fan-in and fan-out
• HP SCSI FC Compliant Data Replication Protocol (HP SCSI-FCP), a full SCSI protocol
implementation that takes advantage of the exchange-based routing available in fabric switches.
For more information, see “Planning the data replication protocol” (page 38).
See the HP P6000 Enterprise Virtual Array Compatibility Reference for more information on remote
replication support by controller software version. See “Documentation” (page 128) for the link to
this document.
NOTE: HP P6000 Continuous Access interacts with HP P6000 Command View or HP P6000
Replication Solutions Manager to manage remote replication. To perform replication tasks, HP
P6000 Command View and HP P6000 Replication Solutions Manager must be installed on a
management server. If you are using the array-based management version of HP P6000 Command
View, you cannot perform remote replication tasks.
Remote replication concepts
Remote replication is the continuous copying of data from selected virtual disks on a source (local)
array to related virtual disks on a destination (remote) array. Applications continue to run while
data is replicated in the background. Remote replication requires a fabric connection between the
source and destination arrays and a software connection (DR group) between source virtual disks
and destination virtual disks.
Write modes
The remote replication write modes are as follows:
• Asynchronous—The array acknowledges I/O completion before data is replicated on the
destination array. Asynchronous write mode can be basic or enhanced, depending on the
software version of the controller.
• Synchronous—The array acknowledges I/O completion after the data is cached on both the
local and destination arrays.
For more information on write modes, see “Choosing a write mode” (page 20).
DR groups
A DR group is a logical group of virtual disks in a remote replication relationship between two
arrays. Hosts write data to the virtual disks in the source array, and the array copies the data to
the virtual disks in the destination array. I/O ordering is maintained across the virtual disks in a
DR group, ensuring I/O consistency on the destination array in the event of a failure of the source
array. The virtual disks in a DR group fail over together, share a write history log (DR group log),
and preserve write order within the group.
Figure 2 (page 9) illustrates the replication of one DR group between a source array and a
destination array. For more information, see “Planning DR groups” (page 36).
8 HP P6000 Continuous Access