When you combine
TCz and
URz using the
Preserve Mirror FlashCopy® function, note the following:
- Install the license of the applicable program products in the storage systems at each site, including the primary, secondary, and remote sites.
- When the URz pair status changes to Pending, the copy pace automatically follows the mirror option specified
- If a Preserve Mirror FlashCopy® configuration already exists, you cannot create an URz pair. You must set up a 3DC cascade, 3DC multi-target, or 3DC delta resync configuration with TCz and URz first, and then use the Preserve Mirror FlashCopy® function.
- In the 3DC cascade configuration, when a FlashCopy® relationship is established, URz pairs combined with the Preserve Mirror FlashCopy® function cannot be resynchronized. Wait until the copy process completes and the relationship is released, or issue the Withdraw command to release the Compatible FlashCopy® relationship. After that, resynchronize the URz pair.
- If a disaster or a failure occurs at the primary site, make sure that the Compatible FlashCopy® relationship is released, and then switch the operation to the secondary site.
- If a FlashCopy® relationship is released during copy process, data consistency between the P-VOL and the S-VOL of the TCz pair combined with the FlashCopy® target volume might not be maintained. To avoid this situation, delete the TCz pair first, and then recreate the pair. For 3DC TCz/URz cascade configuration, delete both the TCz and URz pairs first, and then recreate them.
- Data copied to the URz P-VOL using FlashCopy® is transferred to the URz S-VOL asynchronously. Business Continuity Manager displays the progress ratio of the asynchronous data transfer. In addition, depending on the timing for copy processing of the FlashCopy® relationship and the URz pair, the URz pair might have to wait for FlashCopy® copy processing to complete. As a result, the progress of the asynchronous data transfer of the URz pair might be slow.
- With the Preserve Mirror FlashCopy® function, you can optimize the P-VOL at the primary
site in the 3DC cascade or multi-target configuration with TCz and
URz using the DEFRAG command (volume optimization using
FlashCopy®.
In the 3DC delta resync configuration, you cannot execute the DEFRAG command using the Preserve Mirror FlashCopy® function on the primary volume.
- In the 3DC delta resync configuration, you cannot perform the ReverseRestore or FastReverseRestore operation, which is used to reverse Preserve Mirror FlashCopy® relationships.
- The URz pair combined with the FlashCopy® target volume
cannot be resynchronized under the following conditions. Therefore, release
the Compatible FlashCopy® relationship, and then resynchronize the URz pair.
-
The pair is in the 3DC cascade, 3DC multi-target, or 3DC delta resyc configuration with TCz and URz.
-
The TCz pair is deleted after the FlashCopy® relationship is established by using the Preserve Mirror FlashCopy® function.
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The FlashCopy® pair is not deleted.
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