HP StorageWorks XP Remote Web Console Software - Manual (Page 158)

Managing Power for Storage Systems and Network Relay Devices
This section explains power management for storage systems and network relay devices during
remote copy operations. In particular, this section discusses the following situations:
•
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” (page 158) )
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 occurred, 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
occurred, 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 (that is, 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 occurred, 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 occurred, 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 (that is, 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 occurred, 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.
Powering Off the Primary Storage System
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 (that is, 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 is used with extended consistency groups,
you must split all data volume pairs in the extended consistency groups before powering off the
158 Configuring Storage Systems and Logical Paths