HP XP P9000 Continuous Access Synchronous for Mainframe Systems User Guide

3 Planning for Continuous Access Synchronous Z
This chapter provides information and instructions for planning main and remote system, pair
volumes, data paths, and other elements.
Storage system preparation
The following preparations are required for the storage systems in a Cnt Ac-S Z pair relationship.
• You can pair the volumes on XP P9500 with volumes on another XP P9500,
XP24000/XP20000 Disk Array, or XP12000 Disk Array/XP10000 Disk Array. However, if
pairing with volumes on an earlier model, see the restrictions in “Requirements for XP P9500
with earlier model storage systems” (page 29).
• Remote Web Console must be LAN-attached to the main and remote system. See the HP XP
P9000 Remote Web Console User Guide for information.
• The main and remote system must be set up for Cnt Ac-S Z operations. See “Cache, additional
shared memory requirements” (page 28) and “DASD fast write requirements” (page 29).
Make sure to consider the amount of Cache Residency data that will be stored in cache when
determining the amount of cache for Cnt Ac-S Z operations.
• Set the system option modes, if needed, for your Cnt Ac-S Z configuration on the main and
remote system. See “S-VOL Read and other system options” (page 29) for more information.
• Make sure that the main system is configured to report sense information to the host. The
remote system should also be attached to a host server to report sense information in the event
of a problem with an S-VOL or remote system. If the storage system is not attached to a host,
it should be attached to a main system host server so that monitoring can be performed.
• On the host operating system, make sure that the missing interrupt handler (MIH) value (also
called host I/O patrol time) is set high enough to accommodate the number of pairs, the cable
length between the main and remote system, and the initial copy pace. The recommended
MIH value for Cnt Ac-S Z operations is 60 seconds. For MVS, the MIH value is specified in
the SYS1.PARMLIB file. The recommended MIH value for Compatible XRC is different than for
Cnt Ac-S Z. If you are performing Cnt Ac-S Z and Compatible XRC operations on the same
storage system at the same time, contact your HP representative for assistance.
• If power sequence control cables are used, set the power select switch for the cluster to LOCAL
to prevent the main system from being powered off by the host. Make sure the S-VOL is not
powered off during Cnt Ac-S Z operations.
• Install the data path between the main and remote system. Distribute data paths between
different storage clusters and extenders or switches to provide maximum flexibility and
availability. The logical paths between the main and remote system must be different than the
logical paths between the host and remote system. See “Data path requirements and
configurations” (page 46) for more information.
Cache, additional shared memory requirements
Cache must be operable for the pair’s main and remote system, otherwise pairs cannot be created.
The remote system cache should be configured to adequately support Cnt Ac-S Z remote copy
workloads and any local workload activity.
Additional shared memory is prerequisite in both of the main and remote system.
NOTE: Neither cache nor shared memory can be added to or removed from the storage system
when pair status is Pending. When either of these tasks is to be performed, first split any pairs in
Pending status; then resynchronize the pairs when the cache or shared memory operation is
completed.
28 Planning for Continuous Access Synchronous Z