HP XP Continuous Access Software - Manual (Page 221)

13 Power management for arrays
and network relay devices
This appendix explains power management for arrays and network relay devices during remote copy
operations. In particular, this appendix discusses the following:
• What happens when power is removed from arrays or network relay devices due to an
unexpected reason (see When power is removed due to an unexpected reason )
• What should be noted when you intentionally power off arrays or network relay devices (see
When intentionally turning power off )
The term “network relay devices” refers to hardware used for connecting primary and secondary arrays,
such as ESCON® directors, channel extenders, and switches.
When power is removed due to an unexpected reason
This section explains what happens when power is removed from arrays or network relay devices due to
an unexpected reason.
When power is removed from primary arrays
If power is removed from the primary array during remote copy operations, the primary array assumes
a failure occurred, and splits all data volume pairs. If the primary array splits data volume pairs, the
secondary array also assumes a failure occurred, and splits all data volume pairs.
If power is removed from the primary or secondary array and its backup batteries are fully discharged
while data volume pairs are split, differential data (that is, update data) is not retained. In this unlikely
case, the primary or secondary array assumes all suspended data volumes are updated. If you restore
data volume pairs at the primary site, all primary data volumes are copied to the secondary data volumes.
When power is removed from secondary arrays
If power is removed from the secondary array during remote copy operations, the secondary array
assumes a failure occurred, and splits all data volume pairs. If the secondary array splits data volume
pairs, the primary array also assumes a failure occurred, and splits all data volume pairs.
If power is removed from the primary or secondary array and its backup batteries are fully discharged
while data volume pairs are split, differential data (that is, update data) is not retained. In this unlikely
case, the primary or secondary array assumes all suspended data volumes are updated. If you restore
data volume pairs at the primary site, all primary data volumes are copied to the secondary data volumes.
When power is removed from network relay devices
If power is removed from a network relay device during remote copy operations, the primary and
secondary arrays assume a failure occurred, and split all data volume pairs.
When intentionally turning power off
This section explains what you should note when you intentionally power off arrays or network relay
devices.
Continuous Access XP Journal user guide 221