Changing options used by mirrors

Most pair operations are performed on multiple pairs. This is done using a journal or mirrors. You can change the following options that affect the pairs in a mirror:

• Path Watch Time: The interval from the time a path becomes blocked to the time when the mirror is suspended.

 Except for special circumstances, set the same Path Watch Time value for the mirror's primary side (MCU) and secondary side (RCU). When the primary side (MCU) and secondary side (RCU) are different, the mirrors will not be split (suspended) synchronously. For example, when 5 minutes is set for the mirror's primary side (MCU) and 60 minutes for the secondary side (RCU), the path on the primary side (MCU) will be suspended 5 minutes after the path blockage, but the secondary side (RCU) will be suspended 60 minutes later.

• Path Watch Time Transfer: Transfers the master journal’s Path Watch Time value to the restore journal.

The Path Watch Time Transfer cannot be set at the secondary site. Because the Path Watch Time value needs to be set for the secondary site when performing the delta resync operation, make sure to specify Yes at the primary site of the UR delta resync pair.

• Copy Pace: The pace at which data is copied.

• Transfer Speed: The speed for data transfer.

• Delta Resync Failure: The processing that takes place when the delta resync operation failed.

Prerequisite information

Please be aware of the following when changing mirror options:

• Mirror options can be changed on both primary and secondary systems.

• To change mirror options, the status of the mirror must be one of the following:

• Initial

• Active

• Stopped

• Hold

• Holding

• Hold(Failure)

• When the mirror status is Active, Hold, or Holding, only the Transfer Speed can be changed. When the mirror status is Holding, the Transfer Speed can be changed only if the mirror belongs to the primary system.

Procedure

1. Open the Remote Replication window.

In Command Suite: On the Resources tab, expand the Storage Systems tree, right-click the target storage system, and then click Remote Replication.

In Device Manager - Storage Navigator: In the Storage System tree, click Replication > Remote Replication.

2. Select the Mirrors tab, and then select the mirror whose options you want to change.

3. From the Actions menu, click Remote Replication > Edit Mirror Options.

4. In the Edit Mirror Options window, for Path Watch Time, specify the interval from the time a path becomes blocked to the time when the mirror is suspended. Ranges are from 1 to 59 minutes, 1 to 23 hours, or 1 to 30 days. A numeric value is required.

The interval must be the same for master and restore journals in the same mirror, otherwise the journals suspend at different times. See the next step to use this setting for both journals.

Important: If you want a mirror to split immediately after a path becomes blocked, ask customer support to set system option mode 448 to ON and system option mode 449 to OFF.

5. For Path Watch Time Transfer, specify whether to use the same Path Watch Time value you specified for the master journal for the restore journal. Specify this option in the primary site only.

• Yes: The Path Watch Time value is also used for the restore journal.

• No: The Path Watch Time value is not used for the restore journal. No is the default.

6. For Copy Pace, specify the pace for initial copy activity per volume. Specify this option in the primary site only.

• Slower is the default.

• If specifying Medium, ensure that write I/O is 10 MB/s or less per parity group. If it exceeds 10 MB/s, pairs might be suspended.

• If specifying Faster, ensure that I/O will not occur. If update I/O occurs, pairs might be suspended.

7. For Transfer Speed, specify the data transfer line speed in Mbps (megabits per second). You can specify 256, 100, 10, or 3.

• Use 256 when the transfer speed is 256 Mbps or higher.

• Use 100 when the transfer speed is 100 to 255 Mbps.

• Use 10 when the transfer speed is 10 to 99 Mbps.

• Use 3 when the transfer speed is 3 to 9 Mbps.

 This setting does not effect master journals unless the CCI horctakeover command is used to change a master journal into a restore journal.

8. For Delta Resync Failure, specify the processing that takes place when the delta resync operation cannot be performed. Specify this option in the primary site only.

- Entire Copy: The entire P-VOL is copied to the S-VOL. This is the default. Use Entire Copy if your journals are part of a multiple-journal configuration in a CCI consistency group.

- No Copy: No processing occurs, and the S-VOL is not updated.

9. Click Finish.

10. In the Confirm window, review the settings and enter a task name in the Task Name box.

11. Click Apply to save your settings to the system.