HP XP Racks - Manual (Page 15)

3 Planning for Continuous Access Synchronous
This chapter provides information and instructions for planning primary and secondary system,
pair volumes, data paths, and other elements.
Storage system preparation
The following preparations are required for the storage systems in a Continuous Access Synchronous
pair relationship.
•
You can pair the volumes on XP7 Storage with volumes on another XP7, P9500, or
XP24000/XP20000 Disk Array. However, if pairing with volumes on an earlier model, see
the restrictions in
“Requirements for XP7 with earlier model storage systems” (page 15) .
•
Remote Web Console must be LAN-attached to the primary and secondary system. See the
HP XP7 Remote Web Console User Guide for information.
•
The primary and secondary system must be set up for Continuous Access Synchronous
operations. See
“Cache, additional shared memory requirements” (page 15) . Make sure to
consider the amount of Cache Residency data that will be stored in cache when determining
the amount of cache for Continuous Access Synchronous operations.
•
Make sure that the primary system is configured to report sense information to the host. The
secondary system should also be attached to a host server to report sense information in the
event of a problem with an S-VOL or secondary system. If the storage system is not attached
to a host, it should be attached to a primary system host server so that monitoring can be
performed.
•
If power sequence control cables are used, set the power select switch for the cluster to LOCAL
to prevent the primary system from being powered off by the host. Make sure the S-VOL is
not powered off during Continuous Access Synchronous operations.
•
Install the data path between the primary and secondary system. Distribute data paths between
different storage clusters and extenders or switches to provide maximum flexibility and
availability. The remote paths between the primary and secondary system must be different
than the remote paths between the host and secondary system. See
“Data path requirements
and configurations” (page 32) for more information.
Cache, additional shared memory requirements
Cache must be operable for the pair's primary and secondary system, otherwise pairs cannot be
created. The secondary system cache should be configured to adequately support Continuous
Access Synchronous remote copy workloads and any local workload activity.
Additional shared memory is prerequisite in both of the primary and secondary system.
NOTE: Neither cache nor shared memory can be added to or removed from the storage system
when pair status is COPY. When either of these tasks is to be performed, first split any pairs in
COPY status; then resynchronize the pairs when the cache or shared memory operation is completed.
Requirements for XP7 with earlier model storage systems
You can pair XP7 volumes with P9500 and XP24000/XP20000 Disk Array volumes. However, if
the XP7 volumes are in a consistency group consisting of multiple XP7 systems, XP24000/XP20000
Disk Array cannot be used. In this case, all paired volumes must belong to XP7 or P9500.
•
When connecting XP7 with P9500 XP24000/XP20000 Disk Array, contact your HP
representative for information regarding the supported microcode versions.
•
When using the previous model storage system at the remote site, make sure the primary and
secondary system have unique serial numbers.
Storage system preparation 15