Stabilizing (quiescing) destinations before a Snapshot copy

Why to block data transfers to a destination temporarily

You may need to temporarily stop transfers to a destination. For example, if you want to create a Snapshot copy of a SnapMirror destination volume or qtree that contains a database, you may need to ensure that its contents are stable during the Snapshot copy. You can use the snapmirror quiesce command to block transfers to the destination after the destination reaches a stable state.

What the quiesce command does

The snapmirror quiesce command waits for all existing transfers to both volumes and qtrees to complete and blocks any further updates. If a qtree is not in a stable state (is in transition), the snapmirror quiesce command forces it into a stable state.

You can quiesce only volumes and qtrees that are online and that are SnapMirror destinations.You cannot quiesce a restricted or offline volume or a qtree in a restricted or offline volume.

The snapmirror quiesce command stops a volume or qtree from acting as a SnapMirror destination, but does not prevent it from acting as a SnapMirror source.

Note
The quiesced state persists across reboots.

How to quiesce data transfers

To stabilize and halt updates to data on a SnapMirror destination volume or qtree, complete the following step.

Step	Action
1	Enter the following command on the system on which you want to block transfers: *snapmirror quiesce {dest_volume* \| /vol/volume_name/qtree_name}** dest_volume is the name of the destination volume. qtree_name is the name of a qtree in volume_name.

Example 1

systemA> snapmirror quiesce vol1

snapmirror quiesce: in progress.

snapmirror quiesce: vol1: successfully quiesced

Result

SnapMirror stops any further data transfers to vol1.

Example 2

systemA> snapmirror quiesce vol2

snapmirror quiesce: in progress.

This can be a long-running operation. Use Control-C to interrupt.

......................................

snapmirror quiesce: vol2: successfully quiesced

Result

SnapMirror waits for a transfer to finish and stops any further data transfers to vol2.

Example 3

systemA> snapmirror quiesce /vol/vol1/qtree1

Result

SnapMirror stops data transfers to qtree1 in vol1.

If you use the snapmirror break command on a destination that is quiesced, the quiesce condition is automatically cleared when the destination becomes writable.

Note
If you decide to abort a SnapMirror quiesce operation, press Ctrl-C or enter the snapmirror resume command at any time.

Resuming transfers after quiescing a destination

You can use the snapmirror resume command to restore the capability for data transfer to a volume or qtree you have quiesced.

To resume SnapMirror transfers, complete the following step.

Step	Action
1	Enter the following command for the system on which you want to resume transfers: *snapmirror resume {dest_volume* \| /vol/volume_name/qtree_name}** dest_volume is the name of the destination volume. qtree_name is the name of a qtree in volume_name. Example systemA> snapmirror resume vol2 snapmirror resume: vol2: Successfully resumed Result SnapMirror resumes normal data transfer capability for vol2.

Step

Action

Enter the following command for the system on which you want to resume transfers:

snapmirror resume {dest_volume | 
/vol/volume_name/qtree_name}

dest_volume is the name of the destination volume.

qtree_name is the name of a qtree in volume_name.

Example

systemA> snapmirror resume vol2

snapmirror resume: vol2: Successfully resumed

Result

SnapMirror resumes normal data transfer capability for vol2.