HP XP P9500 Storage - Manual (Page 25)

3 Planning for Continuous Access Synchronous Z
This chapter provides information and instructions for planning main and remote system, pair
volumes, data paths, and the other elements.
Preparing P9500 disk arrays
The following preparations are required for the disk arrays in a Continuous Access Synchronous
Z pair relationship:
•
Remote Web Console must be LAN-attached for the main and remote disk arrays. See the HP
P9000 Remote Web Console User Guide for information.
•
The main and remote disk arrays must be set up for Continuous Access Synchronous Z
operations. See
“Ensuring adequate cache” (page 25) and “Using DASD fast write” (page 25) .
Make sure to consider the amount of Cache Residencydata that will be stored in cache when
determining the amount of cache for Continuous Access Synchronous Z operations.
•
Set the system option modes, if needed, for your Continuous Access Synchronous Z
configuration on the main and remote disk arrays. See
“Enabling R-VOL Read, other system
options” (page 26) for more information.
•
Make sure that the main disk array is configured to report sense information to the host. The
remote disk array should also be attached to a host server for reporting of sense information
in the event of a problem with a R-VOL or remote system. If the remote disk array is not attached
to a host, it is recommended that it be attached to a main site host so that monitoring can be
performed.
•
On the host operating system, make sure that the missing interrupt handler (MIH) value 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 Continuous Access
Synchronous 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
Continuous Access Synchronous Z. If you are performing Continuous Access Synchronous Z
and Compatible XRC on the same disk array at the same time, contact your HP representative
for assistance.
•
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
“Planning data paths” (page 34) for
more information.
Ensuring adequate cache
Cache must be operable for the pair’s main and remote disk arrays; otherwise, the create pair
operation fails. The remote cache should be configured to adequately support Continuous Access
Synchronous Z remote copy workloads, as well as any local workload activity.
Installing or removing cache memory/shared memory
Cache memory/shared memory cannot be installed or removed when a Cnt Ac-S Z pair is in
Pending status. Check the pair status before installing or removing cache memory/shared memory.
If the pair is in Pending status, split the pair, install or remove cache memory/shared memory, and
then resynchronize the pair.
Using DASD fast write
DASD fast write (DFW) is required at the main and remote system only when Required is specified
for the PPRC DFW to R-VOL option. If DFW to an R-VOL is blocked but the pair was established
Preparing P9500 disk arrays 25