Effects of FlexVol volumes on SnapMirror replication

Supported SnapMirror configurations

FlexVol volumes have enhanced SnapMirror replication, but they have also added to the number of SnapMirror configurations possible. The following sections describe supported configurations and note possible exceptions.

Volume SnapMirror

The following volume SnapMirror configurations, both synchronous and asynchronous, are supported:

Traditional volume to traditional volume
FlexVol volume to FlexVol volume
There are two exceptions in which synchronous FlexVol to FlexVol SnapMirror replications are not supported:
- A storage system cannot be both the source of a synchronous SnapMirror relationship using FlexVol volumes and the destination of another synchronous SnapMirror relationship using FlexVol volumes.
- You cannot have two clustered systems that have bidirectional synchronous SnapMirror relationships between them. For example, if Cluster A and Cluster B are two different clustered storage systems, you cannot have some synchronous SnapMirror relationships going from Cluster A to Cluster B and some synchronous SnapMirror relationships going from Cluster B to Cluster A.
  Note
  Volume SnapMirror replication between different volume types is not supported. Specifically, traditional volume to FlexVol volume replication and FlexVol volume to traditional volume replication are not supported.

Qtree SnapMirror

The following qtree SnapMirror configurations are supported:

Traditional volume to traditional volume
Traditional volume to FlexVol volume
FlexVol volume to traditional volume
FlexVol volume to FlexVol volume

Migration from traditional volumes to FlexVol volumes

Only qtree SnapMirror can be used to migrate data from traditional volumes to FlexVol volumes, if you use SnapMirror for this type of migration. Volume SnapMirror cannot be used because it cannot replicate to a different type of volume. See Differences between SnapMirror volume replication and qtree replication.

Resynchronization of FlexVol volumes

Only qtree SnapMirror can be used to resynchronize data, using the snapmirror resync command, after the destination is used and the source needs to match. Volume SnapMirror cannot be used because resynchronization between newer versions of Data ONTAP that contain FlexVol volumes as a feature and older versions of Data ONTAP are not allowed. See Differences between SnapMirror volume replication and qtree replication.

No symmetrical disk geometry issue

FlexVol volumes make disk geometry less of an issue (see Recommendations). Destination volumes do not have to contain the same number of disks or the same size disks as the source volumes.

FlexClone impact on SnapMirror

FlexClone^TM volumes create a nearly instantaneous replica of a volume within the same aggregate. For information about FlexClone volumes, see the FlexVol volume management section of the Storage Management Guide.

Cloning SnapMirror volumes

You can clone SnapMirror volumes. Note that a clone of a SnapMirror destination locks down the Snapshot copy from which the clone was created, in addition to locking down that Snapshot copy in the source volume and every volume in the cascade (if the volume is part of a SnapMirror cascade).

Note
A FlexClone volume can be created from a Snapshot copy in a SnapMirror destination, but a FlexClone volume cannot be the destination of a SnapMirror relationship.

Cloning from a Snapshot copy that is not the most recent Snapshot copy

If a FlexClone volume is created from a Snapshot copy that is not the most recent Snapshot copy, and that Snapshot copy no longer exists on the source volume, then every update will need to delete the Snapshot copy on the destination. In this case, all SnapMirror updates to the destination volume fail until the clone is destroyed or split.

Note
This will not occur if the clone is created from the most recent Snapshot copy in the SnapMirror destination because that Snapshot copy is guaranteed to exist in the source volume.

Effects of deleting the source Snapshot copy

If a source Snapshot copy for a SnapMirror relationship is deleted, SnapMirror fails on subsequent update requests. The failures occur because FlexClone volumes are bound to the source Snapshot copy regardless of whether the FlexClone volume was created on the source or destination volume. Even if the FlexCone volume was created remotely on the destination system, deleting the source Snapshot copy on the source system results in a failed SnapMirror update when attempting to propagate the deletion to the destination.