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Restoring a pair of data volumes, Restoring, A pair of data volumes – HP StorageWorks XP Remote Web Console Software User Manual

Page 130

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130 Performing Continuous Access XP Journal pair operations

• Enable: Hosts can write data to the secondary data volume while the pair is split. This option is

available only when the selected volume is a primary data volume.

Range: Split range. If you select two or more pairs in the same consistency group, the default is LU.

Otherwise, the default is Group.
• LU: Only the specified pairs are split.

NOTE:

If you select pairs with PAIR status and pairs with other than PAIR status in the same

consistency group, an unexpected suspension might occur during the pair operations (Pairsplit-r,

Pairsplit-S, and Pairresync) under heavy I/O load conditions. You can estimate whether the I/O

load is heavy or not from the host I/O frequency. The suspend pair operations should be performed

under light I/O load conditions.

• Group: All pairs in the same consistency groups as the selected pairs are split.

NOTE:

If the following conditions are satisfied and you click Apply, a warning message appears

and processing cannot continue:
• The Preset list contains two or more pairs belonging to the same consistency group.
• The Range column displays Group for at least one of the above pairs.
To continue processing, do one of the following:
• Ensure that the Range column displays LU for all pairs in the same consistency group.
• In the Preset list, select all but one pair in the same consistency group, right click the selected

pairs, and select Delete.

Suspend Mode: Specifies how to deal with update data that was not copied to the secondary data

volume.
• Flush: When splitting the pair, update data is copied to the secondary data volume. This is the

default.
When the secondary array receives a request for splitting a pair, all journal data (that is, update

data) that the pair retains is written to the secondary data volume. After that, the pair’s status

changes from Suspending to PSUS if the pair does not retain any journal data for a certain time

period.

• Purge: When splitting the pair, update data is not copied to the secondary data volume. If you

restore the pair later, update data is copied to the secondary data volume.

Set: Applies settings to the Preset list in the Pair Operation pane.

Cancel: Discards settings.

Restoring a pair of data volumes

Use the Pairresync pane (

Figure 58

) to restore a pair that was split.

NOTE:

If the primary or secondary array is powered off and its backup batteries are fully discharged

while pairs are suspended, the M-VOL/R-VOL bitmaps are not retained. In this unlikely case, the

primary/secondary array marks all cylinders/tracks of all suspended volumes as modified, so the primary

array performs the equivalent of an entire initial copy operation when the pairs are resumed.

The primary array administrator can use the following procedure to restore one or more pairs that were

split. The secondary array administrator cannot perform this procedure.

1.

Ensure that Command View XP or XP Remote Web Console is in Modify mode. For more information,

see the HP StorageWorks Command View XP user guide for XP Disk Arrays or the HP StorageWorks XP

Remote Web Console user guide for XP12000/XP10000/SVS200.

2.

Display the Pair Operation pane (”

Displaying the Pair Operation pane

” on page 115).