HP XP P9500 Storage - Manual (Page 29)

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.
•
If the data paths are disconnected for a short time (less than one minute), S-VOLs may not
change to PSUE status because the storage system does not detect the disconnection.
•
After a power outage, all S-VOLs registered in CTG No. 127 will be changed to PSUE status.
•
The maximum numbers of target volumes is up to 4,096.
•
If write I/O is executed when the P-VOL is in PAIR status and the S-VOL is in PSUE status, the
secondary system does not accept updates, and the primary system suspends the P-VOL.
•
Remote I/O (RIO), which is issued during the change to PSUE status, is accepted by the
secondary system.
•
When the P-VOL’s pair status is changing to PSUE:
A pair cannot be resynchronized. ◦
◦ A pair cannot be created and registered in consistency group No. 127.
◦ A pair cannot be deleted.
Planning consistency groups 29