Powering off and on the external storage system

If you power off and on the external storage system when the local storage system is on, the following Universal Volume Manager operation is required.

Disconnect External Storage Systems: This command is executed when maintenance on an external storage system is performed or stopped. When Disconnect External Storage Systems is selected, the I/O response from host of the external volume mapped as a local storage system volume will stop. At that point, data for the external volume will be written to the external volume (destaged) from data stored in cache memory of the local storage system.

 The same task can be performed on individual volumes with the Disconnect External Storage Volumes command. External volume mapping can be removed by executing Disconnect External Storage Volumes followed by the Delete External Volumes command. See Deleting external volume mapping .

Reconnect External Storage Systems: This command is selected to check whether the external volume status of the defined configuration information matches the status of the volume mapped as a local storage volume. If external volume can be used as a mapped volume, I/O to the external volume is accepted and the volume can be used again.

The Reconnect External Storage Systems command is used to recover from an I/O failure after the Disconnect External Storage Systems command has been executed.

If there is an issue on the path, it is resolved first before the Reconnect External Storage Systems is executed.

 The same task can be performed on individual volumes with the Reconnect External Volumes command.

When the Reconnect External Storage Systems or Reconnect External Volumes command is executed and the external volume can be used, I/O to the external volume is accepted and volume can be used again. The status of the external volume is blocked if it cannot be used.

See Reconnecting external systems and volumes .

Required Role

• Storage Administrator (Provisioning)

To power off the external system

1. Stop read and write I/O to the mapped external volume.

2. If the external volume is defined as a DP-VOL in the internal system, block all DP-VOLs for maintenance as follows:

To block all DP-VOLs in the pool

1. Click Pools in the Storage Systems tree.

2. In the tree, select the pool to be blocked.

3. Select the Virtual Volumes tab.

4. Click Select All Pages.

5. On the menu bar, click Actions, Logical Device, and then Block LDEVs.

6. In the Block LDEVs window, confirm the settings and enter the task name in the Task Name box.

7. Click Apply in the Confirm window.

3. Disconnect the external storage system. See Disconnecting external systems and volumes for instructions.

4. Perform the procedure for powering off the external storage system.

To power on the external system

1. Power on the external storage system.

2. Reconnect the external system. See Reconnecting external systems and volumes for instructions.

3. If the external volume was defined as a DP-VOL in the local system, restore all blocked DP-VOLs.

To restore all DP-VOLs in the pool

1. Click Pools in the Storage Systems tree.

2. In the tree, select the pool to be restored.

3. Select the Virtual Volumes tab.

4. Click Select All Pages.

5. On the menu bar, click Actions, Logical Device, and then Restore LDEVs.

6. In the Restore LDEVs window, confirm the settings and enter the task name in the Task Name box.

7. Click Apply in the Confirm window.

For information on blocking or restoring LDEVs, see the Hitachi Virtual Storage Platform G200, G400, G600 Provisioning Guide.

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