Beginning with ONTAP 9.11.1, AIX is supported with SnapMirror active sync. With an AIX configuration, the primary cluster is the "active" cluster.

In an AIX configuration, failovers are disruptive. With each failover, you will need to perform a re-scan on the host for I/O operations to resume.

Beginning in ONTAP 9.10.1, SnapMirror active sync for HP-UX is supported.

An automatic unplanned failover (AUFO) event on the isolated master cluster may be caused by dual event failure when the connection between the primary and the secondary cluster is lost and the connection between the primary cluster and the mediator is also lost. This is considered a rare event, unlike other AUFO events.

Beginning with ONTAP 9.10.1, SnapMirror active sync supports Solaris 11.4.

To ensure the Solaris client applications are non-disruptive when an unplanned site failover switchover occurs in an SnapMirror active sync environment, modify the default Solaris OS settings.

SnapMirror active sync supports source and destination volumes on FabricPool aggregates with tiering policies of None, Snapshot or Auto. SnapMirror active sync does not support FabricPool aggregates using a tiering policy of All.

In fan-out configurations, your source volume can be mirrored to a SnapMirror active sync destination endpoint and to one or more SnapMirror asynchronous relationships.

SnapMirror active sync supports fan-out configurations with the MirrorAllSnapshots policy and, beginning in ONTAP 9.11.1, the MirrorAndVault policy. Fan-out configurations are not supported in SnapMirror active sync with the XDPDefault policy.

Beginning with ONTAP 9.15.1, SnapMirror active sync supports automatic reconfiguration in the fan-out leg after a failover event. If the failover from the primary to the secondary site has succeeded, the tertiary site is automatically reconfigured to treat the secondary site as the source. Reconfiguration is triggered by either a planned or unplanned failover. Reconfiguration also occurs upon failback to the primary site.

For information about managing your fan-out configuration in earlier releases of ONTAP, see resume protection in the fan-out configuration.

Beginning in ONTAP 9.13.1, you can use NDMP to copy and restore data with SnapMirror active sync. Using NDMP allows you to move data onto the SnapMirror active sync source to complete a restore without pausing protection. This is particularly useful in fan-out configurations.

SnapMirror active sync is supported with SnapCenter beginning with SnapCenter 5.0. SnapCenter enables the creation of Snapshots that can be used to protect and recover applications and virtual machines, enabling always available storage solutions with application-level granularity.

SnapMirror active sync supports partial and single file SnapRestore.

Beginning with ONTAP 9.11.1, single-file SnapRestore is supported for SnapMirror active sync volumes. You can restore a single file from a Snapshot copy replicated from the SnapMirror active sync source to the destination. Because volumes can contain one or more LUNs, this feature helps you implement a less disruptive restore operation, granularly restoring a single LUN without disrupting the other LUNs. Single File SnapRestore has two options: in-place and out-of-place.

Beginning in ONTAP 9.12.1, partial LUN restore is supported for SnapMirror active sync volumes. You can restore a data from application-created Snapshot copies that have been replicated between the SnapMirror active sync source (volume) and the destination (Snapshot copy) volumes. Partial LUN or file restore may be necessary if you need to restore a database on a host that stores multiple databases on the same LUN. Using this functionality requires you to know the starting byte offset of the data and byte count.

Support for large LUNs and large volumes (greater than 100 TB) depends on the version of ONTAP you are using and your platform.