HP StorageWorks XP Remote Web Console Software - Manual (Page 143)

Hitachi TrueCopy for z/OS user guide 143
To produce a PiT duplicate of an existing TC390A consistency group:
1. Disable the applications accessing the TC390A M-VOLs to stop all update activity to all M-VOLs in the
group.
2. After all M-VOL updates have completed, suspend the TC390A group using the Group and Drain
suspend options. If you are suspending the group at the main site, issue the suspend/group command
to one M-VOL in the MCU. If you are suspending the group at the remote site, issue the suspend/group
command to one R-VOL in the RCU.
NOTE: The copy pending timeout setting for the group determines the maximum amount of time
that the suspend/drain operation can take.
3. When the status for all TC390A pairs in the group has changed to suspended, the duplicate set of
volumes is complete. If needed, you can restart the application at the main site.
Powering off/on TrueCopy components
The user is responsible for controlling power-off activities for disk arrays involved in TC390 operations. If
you need to power off the XP12000/XP10000, call your HP representative or HP technical support for
assistance. This section provides instructions for performing planned outages of TC390 components.
If power is removed from an MCU while TC390 operations are in progress, the TC390 pairs are not
affected, but the update sequence consistency of the TC390A groups at the RCU may be affected. For
more information, see ” Planned outage of the MCU ” on page 143. When power is restored to an MCU,
the MCU communicates with its RCU(s) to confirm the pair status of the R-VOLs. Verify that TC390
communications are fully restored (all RCU paths have normal status) before beginning I/O operations to
the M-VOLs. If the MCU accepts a write I/O operation for an M-VOL before this confirmation is complete,
the MCU will suspend the pair and change the status of the M-VOL to suspended-by RCU (the MCU will not
be able to change the pair status of the R-VOL).
If power is removed from an RCU or remote copy connection while TC390 operations are in progress, the
MCU(s) will detect the communication failure, suspend all affected pairs, and generate SIMs and console
messages reporting the failures. The MCU will change the status of the M-VOLs to suspended-by RCU, but
will not be able to change the status of the R-VOLs.
NOTE: If an MCU/RCU is powered off and its backup batteries are fully discharged while TC390 pairs
are suspended, the M-VOL/R-VOL cylinder maps will not be retained. In this unlikely case, the MCU/RCU
will mark all cylinders of all suspended TC390 volumes as modified so that the MCU will perform the
equivalent of an entire initial copy operation when the pairs are resumed. (The R-VOL cylinder map is used
only for TC390A operations.)
Planned outage of the MCU
A planned MCU outage does not affect TC390 Synchronous pairs. For TC390A operations, the MCU must
communicate with the RCU even when there are no M-VOL update I/Os from the primary system. During
the power-off sequence, the MCU will automatically suspend all TC390A pairs in the duplex and duplex
pending state (suspend type = MCU P/S-OFF). During power-on-reset sequence, the MCU will
automatically resume these suspended pairs (pairs with other suspend types are not automatically
resumed).
If a TC390A group contains M-VOLs in the MCU being powered off and in other MCU(s) that is/are not
being powered off, the pairs behind the other MCU(s) will not be suspended and will continue to be
updated.
To maintain a fully consistent group at the RCU during the planned MCU outage:
1. Disable the applications using all M-VOLs in the consistency group.
2. Suspend the group at the RCU using the Group suspend option. You can use the Purge or Drain
suspend option because the M-VOL updates have stopped.
3. Perform the planned outage of the TC390 MCU.