HP StorageWorks XP Remote Web Console Software - Manual (Page 196)

A Managing Power for 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 topics:
•
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 section
Turning Off Power Intentionally ).
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 Primary Storage System
If power is removed from the primary storage system during remote copy operations, the primary
storage system assumes that a failure occurs, and then splits all data volume pairs. If the primary
storage system splits data volume pairs, the secondary 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 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.
196 Managing Power for Storage Systems and Network Relay Devices