Cascade Restrictions With S-Vol Of Shadowimage - Hitachi AMS2100 User Manual

NOTE: When using SnapShot with ShadowImage
•
•

Cascade restrictions with S-VOL of ShadowImage

1-24
Hitachi AMS 2000 Family Copy-on-Write SnapShot User Guide
Failure in this table excludes a condition in which access of an LU is
not possible (for example, LU blockage).
When one P-VOL configures a pair with one or more S-VOLs, decide
which item is applied as the pair status of the P-VOL of the above-
mentioned ShadowImage with the following procedure:
- If all the pairs that the P-VOL concerned configures are in the
Split status, the item of Split is applied.
- If all the pairs that the P-VOL concerned configures are in the
Split status or the Failure status, the item of Split is applied.
However, when including the pair that became Failure during
restore, the items of Failure (Restore) are applied.
- If a pair in the Paired status, the Synchronizing status, or the
Reverse Synchronizing status is included in the pair that the P-
VOL concerned configures, the item of Paired, Synchronizing,
and Reverse Synchronizing is applied, respectively.
Cascade of an LU of SnapShot with an S-VOL of ShadowImage, is
supported only when the S-VOL of ShadowImage and a P-VOL of
SnapShot are the same LU. Also, operations of the ShadowImage and
SnapShot pairs are restricted depending on statuses of the pairs.
• Restriction of pair creation order.
SnapShot with an S-VOL of ShadowImage, create a ShadowImage
pair first. When a SnapShot pair is created earlier, delete the
SnapShot pair once and create a pair using ShadowImage
• Restriction of Split Pending.
status is Split Pending, the SnapShot pair cannot be changed to
the Split status. Execute it again after changing the ShadowImage
pair status to other than Split Pending.
• Changing the SnapShot pair to Split while copying
ShadowImage.
status while the ShadowImage pair status is Synchronizing or
Paired Internally Synchronizing, the V-VOL data of SnapShot
cannot be guaranteed. This is because the status where the
background copy of ShadowImage is operating is determined as the
V-VOL data of SnapShot.
• Performing pair re-synchronization when the
ShadowImage pair status is Failure.
synchronized when the ShadowImage pair status is Failure, all
data is copied from the P-VOL to the S-VOL of ShadowImage. When
the SnapShot pair status is Split, all data of the P-VOL of SnapShot
is saved to the V-VOL. Be careful of the free capacity of the data
pool used by the V-VOL.
SnapShot overview
When cascading a P-VOL of
When the ShadowImage pair
When the SnapShot pair is changed to the Split
If a pair is re