HP XP7 Storage - Manual (Page 83)

S-VOL access P-VOL access Description BCM status RWC status
- - Although the user performed the data resync, difference
data between the master journal and restore journal NODELTA (74) (No parallel
RWC status)
cannot be copied to the S-VOL in the current status.
Running the delta resync in that status may fail. If the
delta resync fails when [Entire] is specified for delta
resync Failure field in the RWC Change Journal Option
dialog box, and all differential data is copied to S-VOL.
1. Holding indicates either that differential data used for a delta resync operation does not exist or that the system cannot judge
whether the delta resync can be performed without the differential data.
When differential data does not exist in the secondary Cnt Ac-S Z site, even after the S-VOL is updated, the differential data
might be discarded due to the one of the following reasons:
• The cache or shared memory was added to or removed from the system during maintenance work.
• The system was powered off during maintenance work.
• The Cnt Ac-J Z or Cnt Ac-S Z pair was suspended and then resynchronized.
After the system is back to normal, differential data is stored again in the Cnt Ac-S Z S-VOL if you update the data in the local
site.
The delta resync operation can be executed without differential data if the local site has not received a data update or if data
in the Cnt Ac-S Z S-VOL and the Cnt Ac-J Z S-VOL is the same.
Even if the delta resync operation without differential data is executable, the pair status changes to Hold regardless of the
differential data existing if the conditions of the differential data discarding are satisfied as mentioned above. To change the
status of the pair to Hold, update the data in the primary system after the recovery from the condition of the differential data
discarding.
If you cannot connect to the remote site of Cnt Ac-S Z due to failures or disasters, the transition from Holding to Hold is not
performed correctly.
Additional information on pair status
•
When a pair is split by the user or suspended by the system, the primary system notifies the
host(s) with a service information message (SIM). If SNMP is installed and operational for
XP7, this SIM results in an SNMP trap indicating the reason for suspension.
•
Transitional states (Deleting) occur when a request is accepted to change pair status to Suspend
by user, Suspend by system, or to delete the pair, but is not yet complete. Transition states
are not reported to the host.
•
The user or the primary or secondary systems can initiate the Suspend by user/Suspend by
system status change.
•
Only the user can release a pair.
•
When you perform an operation, the system reports final status at the end of the operation.
•
If an error causes the status to change to Suspend, the status is reported at the beginning of
the transition.
•
When pair status is Pending, neither cache nor shared memory can be added to or removed
from the system. When either tasks is to be performed, split any pairs in Pending, status, then
resynchronize when the cache or shared memory operation is completed.
Suspend types
You can suspend a pair after the initial copy operation is complete. When you suspend a pair,
the primary and secondary systems ensure synchronization by completing or discarding any
pending update copy operations. This depends on the Suspend Mode option that you specify in
the Suspend Pair operation.
Monitoring pair activity, status, license capacity 83