HP StorageWorks XP Remote Web Console Software - Manual (Page 171)

B Retention of Pair Consistency using the Consistency Group
of the XP Continuous Access Synchronous
To maintain pair consistency within the storage system, it is possible to do the following:
•
Automatic Registration for the Consistency Groups
When creating an XP Continuous Access Synchronous pair using the Remote Web Console,
the created XP Continuous Access Synchronous pair can be registered in a specific consistency
group automatically. If an XP Continuous Access Synchronous pair is suspended for any
reason, all the XP Continuous Access synchronous P-VOLs registered in this specific consistency
group will be suspended.
•
Changing the Status of S-VOL When RCU is Disconnected.
When the RCU detects that all of the connections for the MCU are disconnected, all of the XP
Continuous synchronous S-VOLs registered in the specific consistency group will be changed
to PSUE status.
Automatic Registration for the Consistency Groups
When creating an XP Continuous Access Synchronous pair with Remote Web Console, the created
XP Continuous Access Synchronous pair can be registered in consistency group (CTG) Number
127. If an XP Continuous Access Synchronous pair is suspended for any reason, all the XP
Continuous Access Synchronous P-VOLs registered in CTG Number 127 will be suspended. With
this operation, the data consistency of pairs on each of the S-VOLs in the storage system can be
maintained.
Note the following items when the suspending operation for P-VOL is executed.
•
P-VOLs can be suspended only when the Function Switch 30 is set on the MCU.
•
Only XP Continuous Access Synchronous P-VOLs registered in CTG Number 127 will be
suspended.
After Function Switch 30 is set on MCU, only XP Continuous Access synchronous P-VOLs will
be suspended if they are created by Remote Web Console automatically registered in CTG
Number 127) or if they are created by RAID Manager and registered in CTG Number 127.
•
If the XP Continuous Access Synchronous pairs have already been registered in CTG 127,
those pairs will also be suspended.
•
When a failure occurs or the system is suspended specifically by RAID Manager, all the P-VOLs
will be suspended. All P-VOLs cannot be suspended by normal operation.
•
Both P-VOLs and S-VOLs are registered in CTG Number 127. Therefore, when the both volumes
are paired bi-directionally, all of the target XP Continuous Access Synchronous pairs are
registered in the CTG Number 127 when the take over is executed.
•
The numbers of target pairs can be up to 4,096.
•
Pairs are not suspended if there is no Write I/O operation to any XP Continuous Access
synchronous pairs registered in CTG Number 127.
•
When the status of P-VOL is PAIR and S-VOL is PSUE, if a Write I/O is executed, all P-VOLs
registered in the CTG Number 127 are suspended by failure.
To restore the pair status of the S-VOL to PAIR, when the status of P-VOL is in PAIR and S-VOL
is in PSUE, then execute resynchronization after suspending P-VOL using Remote Web Console.
To suspend P-VOL using RAID Manager, apply the –1 option.
•
When an S-VOL is suspended due to an intermittent communication failure, the P-VOL might
not be suspended (P-VOL with no I/O process stays in PAIR).
Automatic Registration for the Consistency Groups 171