HP XP7 Storage User Manual
Page 133
For more information, see
“Delta resync configuration ” (page 127)
.
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Required pair and volume statuses:
The Cnt Ac-S volume used as the 3DC multi-target P-VOL: PAIR
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The Cnt Ac-S S-VOL used as the delta resync P-VOL: SSWS.
Check this status after executing the RAID Manager horctakeover command
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The Cnt Ac-J delta resync pair: HOLD or HOLDING. If the pair status is HLDE, change to
HOLD by performing the pairresync operation.
This applies to all pairs in the journal in which the Cnt Ac-J pair for delta resync resides.
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The Cnt Ac-J volume used as the 3DC multi-target and the delta resync pair S-VOL and
uses two mirror IDs — one for the 3DC multi-target pair and one for the delta resync pair:
- 3DC multi-target S-VOL: PAIR, PSUS, or PSUE
- Delta resync S-VOL: HOLD.
NOTE:
The Cnt Ac-J S-VOL uses two mirror IDs because of its dual use in the 3DC
multi-target and delta resync configurations. The statuses shown above are required for
the two mirrors as well as for the journal in which the Cnt Ac-J pair for delta resync resides.
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If the delta resync S-VOL has been backed up on the remote site using BC or FS, make sure
to review the information for the Delta resync Failure step in (
).
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Differential data is stored in the master journal but may not be completely present after a
failure at the local site when the pair was being resynchronized (or after creating the delta
resync pair configuration).
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If data in the restore journal exceeds 80% of capacity, old journal data is automatically
deleted. This can occur when the suspended pair has not been re-synchronized for a long
time.
In this case, based on journal option settings, the entire P-VOL is copied to the S-VOL. In a
delta resync operation, processing is not performed.
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Journal data may also be destroyed in the following cases:
When you restore the Cnt Ac-S or Cnt Ac-J pair in the multi-target configuration, then also
update the delta resync pair.
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When retry-processing occurs because of a delay of the P-VOL update.
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When the update of a Cnt Ac-S S-VOL is delayed.
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The Cnt Ac-J pair status in a delta resync configuration could become PSUS or PSUE if you
split the pair, or if there is a failure when copying all data from the P-VOL to the S-VOL. If you
then run the delta resync operation, all data might be copied from P-VOL to S-VOL regardless
of journal option settings.
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If the pair’s mirror is in Halting or Stopping status, the resynchronization command is rejected.
Problems that can occur in the delta resync operation
Journal data will not exist, and therefore the delta resync operation will fail, in the following cases:
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After creating the Cnt Ac-J pair, the primary delta resync P-VOL is updated but not the Cnt
Ac-J P-VOL.
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When the multi-target P-VOL is resynchronized after the Cnt Ac-S pair was split.
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When the Cnt Ac-J S-VOL is resynchronized after it was split.
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When the Cnt Ac-J pair is resynchronized after being split and then the journal volume at the
Cnt Ac-S remote site exceeds 70%.
Delta resync configuration
133