ONTAP 9.9.1 or later

ONTAP Mediator 1.2 or later

A Linux server or virtual machine for the ONTAP Mediator running one of the following:

SnapMirror synchronous license must be applied on both clusters.

SnapMirror license must be applied on both clusters.

Inter-cluster latency round trip time (RTT) must be less than 10 milliseconds.

Beginning with ONTAP 9.14.1, [SCSI-3 persistent reservations] are supported with SnapMirror active sync.

Only SAN protocols are supported (not NFS/SMB).

Only Fibre Channel and iSCSI protocols are supported.

The default IPspace is required by SnapMirror active sync for cluster peer relationships. Custom IPspace is not supported.

The ONTAP Mediator must be provisioned externally and attached to ONTAP for transparent application failover.

To be fully functional and to enable automatic unplanned failover, the external ONTAP mediator should be provisioned and configured with ONTAP clusters.

The ONTAP Mediator must be installed in a third failure domain, separate from the two ONTAP clusters.

When installing the ONTAP Mediator, you should replace the self-signed certificate with a valid certificate signed by a mainstream reliable CA.

For more information about the ONTAP Mediator, see Prepare to install the ONTAP Mediator service.

SnapMirror active sync relationships are not supported on read-write destination volumes. Before you can use a read-write volume, you must convert it to a DP volume by creating a volume-level SnapMirror relationship and then deleting the relationship. For details, see Convert an existing SnapMirror relationships to SnapMirror active sync.

Storage VMs using SnapMirror active sync cannot be joined to Active Directory as a client computed.

ONTAP Mediator overview