HP StorageWorks XP24000 Continuous Access Software User and Reference Guide, v01 (T5278-96002, June 2007)

Tabl e 25 Ana lyzin g the Consistency of Continuous Access A synchronous S-VOLs
Status of S-VOL Usable for
Recovery?
Description
PAIR
COPY
SMPL
No
No
No
These states do
not
usually occur during Continuous Access
Asynchronous
disaster recovery because the RCU suspends all
Continuous Ac
cess Asynchronous S-VOLs when communication with
the
MCU is lost
.
Continuous Access Asynchronous S-VOLs in these
states shoul
d
not be used for disaster recovery.
Note: Simple
x
volumes cannot be distinguished from S-VOLs which
have already
been
released by the p airsplit-S operation.
PSUE-Group
Yes
The updatesequenceconsistency across theseS-VOLs is ensured.
These S- VOLs can be used for disaster recovery at the secondary
system.
Note: The time of the latest update indicated on the Detailed
Information dialog box (MCU SVP time) will help to determine the last
time these
S-VOLs were updated.
PSUE-LU
No
The contents of this S-VOL may be behind the other S-VOLs in the
consistency group. If this volume must be consistent with the other
volumes in the sam e group, this S-VOL should not be used for disaster
recovery.
The cause for this status is:
•
The Continuous Access Asynchronous Error Level pair option for
this
pair is LU (not Group), AND
•
This pair was suspended before the disaster/failure, at the
beginning
of the rolling disaster, or during the initial copy
operation.
Transferring Operations Back to the Primary Site
Once the applications are running at the secondary (remote) site, the next activity is to restore the primary
(main) site and transfer operations back to the primary site. To transfer operations to the primary site:
1. Bring up the host server(s) at the p rimary site, and make sure that all Continuous Access
components are fully operational.
2. At the primary site, release all Continuous Access pairs at the MCUs. The Delete Pair by Force
option must be used because the previous S-VOLs are in the SMPL state at the secondary site.
3. At the main site, delete all Continuous Access Asynchronous consistency groups at the MCUs.
4. At the main site, delete the RCUs. Remember to connect with each MCU and each CU to
make sure that all the RCUs have been deleted.
5. If you plan to use the same remote copy conne ctions to copy back, change the existing initiator
ports to ordinary target ports.
6. If you plan to use the same switches, change the operating mod e to the opposite direction (see
“Remote Copy Connections” on page 47).
If you plan to use the same channel extenders, change the operating mode to the opposite
direction. The boxes/nodes connected to the MCUs must be set to channel-mode, and the
boxes/nodes connected to the RCUs must be set to device-mode.
7. At the remote site, configure the appropriate ports to enable Continuous Access operations in
the
reverse direction (change target por ts to initiator ports). This enables the original RCUs to
send Continuous Access remote copy operations to the original MCUs to bring the original
P-VOLs up to date.
8. At the remote site, establish the same Continuous Access Asynchronous groups and Continuous
Access pairs in the reverse direction to synchronize the original P-VOLs with the S-VOLs. Make
sure to use the Entire Volume initial copy op tion.
132 Usage Scenarios