Ensuring Consistent Status For Pair Suspensions, Path Failure - HP StorageWorks P9000 User Manual

Ensuring consistent status for pair suspensions, path failure

This section discusses the following specific conditions and subsequent behavior. This discussion
applies to both Remote Web Console and RAID Manager users.
When a pair in consistency group 127 suspends for any reason, you can ensure that all
P-VOLs in the group become suspended.
When the Continuous Access Synchronous data paths between the secondary and primary
system fail, you can insure that all S-VOLs in consistency group 127 are placed in PSUE status.
To cause one or both of these behaviors
1. Turn Function Switch 30 On. Click the System Options tab to locate the Function Switch node
at the bottom of the node tree on the left side of the screen.
Turn the switch on in the primary and secondary systems to get both behaviors.
Turn the switch on only in the system where you want the related behavior (primary for
consistent P-VOL suspensions, secondary for consistent S-VOL PSUE status).
2. Create the pair or pairs and assign them to consistency group 127.
In RAID Manager, assign the pair or pairs to this group number when you create the
pairs.
In Remote Web Console, the pair or pairs are automatically assigned to consistency
group 127 when function switch 30 is On and the pair or pairs are created.
Note the following behaviors and restrictions regarding the consistent suspending of all P-VOLs as
described above:
When a failure occurs or if suspended specifically by RAID Manager, all the P-VOLs will be
suspended. All the P-VOLs cannot be suspended by the normal operation.
When P-VOLs and S-VOLs are registered in CTG No. 127, and both volumes are paired
bidirectionally, all of the target pairs volumes are registered in CTG No. 127 when takeover
is executed.
The maximum number of pairs in CTG 127 is 4,096.
For P-VOLs to be suspended, a failure must occur, then a write I/O operation must occur in
any of the pairs.
When the status of the P-VOL is in PAIR and status of the S-VOL is PSUE, if a Write I/O is
executed, all P-VOLs registered in the CTG No. 127 are suspended by failure.
When P-VOL status is PAIR and S-VOL status is PSUE, you can restore PAIR status to the S-VOL
by suspending the P-VOL and then resynchronizing the pair. With RAID Manager, Use the -l
option.
When the S-VOL is suspended due to an intermittent communication failure, the P-VOL might
not be suspended (P-VOL with no I/O processing stays in PAIR).
Note the following behaviors and restrictions regarding the consistent changing of all S-VOLs to
PSUE status as described above:
S-VOLs must be in PAIR or COPY status. They cannot be changed to PSUE status when in PSUS
or SSUS status.
All connections to the primary system must be disconnected.
S-VOLs cannot be changed to PSUE status if the MinimumPath field is set to a value other than
1 on the primary system.
It may take up to 10 minutes to change status to PSUE if there are many pairs.
All S-VOLs will be changed to PSUE status even if all data paths are recovered in the middle
of the process.
26 Planning for Continuous Access Synchronous