HP XP P9500 Storage - Manual (Page 131)

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The P-VOL in the first pair cannot be in COPY status when creating the second pair. In this
case, the second pair will not be created.
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When multiple mirrors are registered in the journal, the P-VOL of one of the mirrors cannot be
in COPY status when resynchronizing a pair of another mirror. In this case, the second pair
will not be resynchronized.
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When splitting the pair whose S-VOL is also the delta resync S-VOL, host I/O to the S-VOL
will not be allowed even when you specify Enable for S-VOL Write in the split procedure.
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When you delete either multi-target pair, the delta resync pair is also deleted.
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Delta resync operation requirements. These requirements are required for all volumes in the
respective journals.
◦ Remote command devices are required for the two mirror IDs at the delta resync primary
and secondary sites.
◦ The data paths must be operational.
◦ RAID Manager must be used for the delta resync operation.
◦ Required pair and volume statuses for the delta resync operation.
- Delta resync P-VOL and S-VOL: HOLD
- Cnt Ac-J P-VOL: SSWS
- Cnt Ac-J S-VOL: PAIR, PSUS, PSUE
◦ Differential data is stored in the delta resync master journal but may not be completely
present after a failure at delta resync primary site.
Problems that can occur with delta resync
Journal data will not exist, and therefore the delta resync operation will not succeed, if the following
occurs. Avoid these situations.
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After splitting the intermediate-remote pair, the S-VOL is updated.
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After the intermediate-remote pair is split and the journal volume at the intermediate site then
exceeds 70-percent as a result of updates from the primary site.
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When the delta resync P-VOL is updated and then data in the journal volume exceeds
70-percent.
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The Delta resync Failure option in the Change Mirror Options dialog box is disabled for the
delta resync in a 3Cnt Ac-J DC multi-target configuration.
The following provides solutions to other delta resync problems.
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If the delta resync pair status becomes HLDE, you cannot restore it to HOLD by resynchronizing
the pair. You must delete the delta resync pair and recreate it.
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If the delta resync pair’s status does not change after the delta resync operation, some of the
requirements explained in this topic may not have been fulfilled. In that case, check the status
of the Cnt Ac-J pair and Cnt Ac-J pair for delta resync operation, and make sure that all pairs
are in the required status.
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If the delta resync pair becomes suspended due to failure following the operation, if the
problem is related to the P-VOL, resynchronize the pair. If the problem is related to the S-VOL,
delete then recreate the pair.
Setting up the 3 Cnt Ac-J DC multi-target configuration
Set up a 3 Cnt Ac-J DC multi-target configuration using the following procedure. RAID Manager
is used to set up the configuration.
To set up a 3DC multi-target using Cnt Ac-J and Continuous Access Synchronous, see
“Procedure
for setting up 3DC multi-target” (page 144) .
3 Cnt Ac-J DC multi-target configuration 131