Restoring Thin Image pairs

Restoring an HTI pair overwrites the existing P-VOL data with the differential data on the S-VOL.

Restoring of an HTI pair may end abnormally in either of the following conditions.

• You are storing snapshot data for a consistency group that already includes the HTI pair.

• You are using the P-VOL of the HTI pair as the P-VOL of another HTI pair and you are storing snapshot data for a consistency group including the latter HTI pair.

 Failures can occur while restoring HTI pairs, which suspends the pairs (“PSUE” status).

During a failure, the storage system does the following:

• Blocks and suspends the HTI pair (“PSUE” status), including the HTI pairs has snapshot data in the pool. You must recover the suspended pairs (“PSUE” status) (see Workflow for restoring suspended Thin Image pairs).

• Writes data to the HTI pair volumes.

• Exceeds the data pool capacity of snapshot data.

If a failure occurs, delete the unneeded snapshot data by restoring the suspended pairs.

For more information:

• About restoring suspended HTI pairs, see Workflow for restoring suspended Thin Image pairs.

The amount of time required for restoration depends on the following, even if the pair synchronization rate is 100 percent:

• The amount of capacity the pool is using.

• The number of pairs being resynchronized concurrently.

 The pair synchronization rate may not change when you view the rate while restoring the HTI pair. To view the up-to-date rate, wait until the task has completed.

For more information about monitoring the pair synchronization rates, see Viewing pair synchronization rates.

Prerequisites

• You have the Storage Administrator (Local Copy) role.

• The HTI pair is split (“PSUS” status).

1. Navigate to the Local Replication window.

In Hitachi Command Suite:

1. On the Resources tab, click Storage Systems, and then expand the storage system tree.

2. Right-click the target storage system, and then select Local Replication.

In Device Manager - Storage Navigator:

1. In the Explorer pane, click Storage Systems, expand the storage system tree, expand Replication, and then click Local Replication.

2. In the Local Replication window, select a P-VOL in the TI Primary Volumes tab or a snapshot group in the Snapshot Groups tab.

3. From the Action menu, select Local Replication > Operate TI Pairs.

4. In the TI Pairs window, select the pairs you want to resynchronize, and then click Resync Pairs.

5. For Resync Type, select Reverse Copy (Secondary > Primary), which fully restores the P-VOL data from the S-VOL.

 You can specify up to 32 P-VOLs using HDvM - SN.

6. Click Finish.

7. In the Confirm window, complete the following.

• Confirm the settings.

• Enter a name for your task in Task Name.

• (Optional) Select Go to tasks window for status if you want the Tasks window to open after you click Apply.

8. Click Apply.

The task is registered, and if the Go to tasks window for status check box was selected, the Tasks window appears.

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