HP StorageWorks XP Remote Web Console Software - Manual (Page 209)

13 Power Management for Disk
Storage Systems and Network
Relay Devices
This appendix explains power management for storage system s and network relay devices during remote
copy operations. In particular, this appendix discusses the following:
• What happens when power is removed from storage systems or network relay devices due to
some unexpected reason (see the next section).
• What should be noted when you power off storage systems or network relay devices intentionally
(see “ Turning Off Power Intentionally ” on page 209)
Here, the term "network relay devices" refers to hardware used for connecting the primary and secondary
storage systems, such as ESCON directors, channel extenders, and switches.
When Power Stops Unexpectedly
This section explains what happens when power is removed from storage systems or network relay
devices due to some unexpected reason.
When the Power is Removed from the Secondary Storage System
If power is removed from the secondary storage system during remote copy operations, the secondary
storage system assumes that a failure occurs, and then splits all data volume pairs. If the secondary
storage system splits data volume pairs, the primary storage system also assumes that a failure occurs,
and then splits all data volume pairs.
If power is removed from the primary or secondary storage system and its backup batteries are fully
discharged while data volume pairs are split, differential data (i.e., update data) will not be retained. In
this unlikely case, the primary or secondary storage system assumes all the suspended data volumes
are updated. If you restore the data volume pairs at the primary site, all the primary data volumes
will be copied to the secondary data volumes.
When the Power is Removed from Network Relay Devices
If power is removed from a network relay device during remote copy operations, the primary and
secondary storage systems assume that a failure occurs, and then split all data volume pairs.
Turning Off Power Intentionally
This section explains what should be noted when you power off storage systems or network relay devices
intentionally.
When You Power Off the Primary Storage System
If you want to power off the primary storage system during remote copy operations, you must ensure,
before powering off the storage system, that all data volume pairs or mirrors (i.e., pairs of journal groups)
are split, and that the status of all the data volume pairs is Suspend.
If more than one primary and secondary storage systems are used with extended consistency groups,
you must split all data volume pairs in the extended consistency groups before powering off the primary
Hitachi Universal Replicator for z/OS user guide for XP12000/XP10000 Disk Arrays and SVS 200 209