HP XP Continuous Access Software - Manual (Page 156)

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) is not
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 are 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) is not
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 are 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 the Power Off Intentionally
This section explains what should be noted when you power off storage systems or network relay
devices intentionally.
To power off the primary or secondary storage system, contact your HP technical support and ask
them to power off the storage system. To power off both the primary and secondary storage systems
at the same time, see
“Power Off the Primary and Secondary Storage Systems at the Same Time”
(page 157) .
Power 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 PSUS.
If the delta resync function that uses a remote command devices is used, the SIM (SIM reference
code = EFD0) that suggests that the device connected to the external storage system has been
blocked, is reported to the destination storage system(s) because the command devices are blocked
due to a power-off of the storage system.
If data volume pairs are split and the primary storage system is powered off as mentioned above,
you can resume remote copy operations by taking the following steps:
1. Power on the primary storage system.
2. If the primary storage system is ready to resume remote copy operations, restore the data
volume pairs that have been split, and then confirm that the status of the data volume pairs is
COPY or PAIR. This operation must be performed at the primary site.
After you take these steps, remote copy operations resume. The primary storage system can respond
to
read journal commands issued by the secondary storage system.
156 Configuring Storage Systems and Logical Paths