XDP replaces DP as the SnapMirror default

Contributors

Starting with ONTAP 9.3, SnapMirror extended data protection (XDP) mode replaces SnapMirror data protection (DP) mode as the SnapMirror default.

Until ONTAP 9.3, SnapMirror invoked in DP mode and SnapMirror invoked in XDP mode used different replication engines, with different approaches to version-dependence:

  • SnapMirror invoked in DP mode used a version-dependent replication engine in which the ONTAP version was required to be the same on primary and secondary storage:

    cluster_dst::>  snapmirror create -type DP -source-path ... -destination-path ...
  • SnapMirror invoked in XDP mode used a version-flexible replication engine that supported different ONTAP versions on primary and secondary storage:

    cluster_dst::>  snapmirror create -type XDP -source-path ... -destination-path ...

With improvements in performance, the significant benefits of version-flexible SnapMirror outweigh the slight advantage in replication throughput obtained with version-dependent mode. For this reason, starting with ONTAP 9.3, XDP mode has been made the new default, and any invocations of DP mode on the command line or in new or existing scripts are automatically converted to XDP mode.

Existing relationships are not affected. If a relationship is already of type DP, it will continue to be of type DP. Starting with ONTAP 9.5, MirrorAndVault is the new default policy when no data protection mode is specified or when XDP mode is specified as the relationship type. The table below shows the behavior you can expect.

If you specify…​ The type is…​ The default policy (if you do not specify a policy) is…​

DP

XDP

MirrorAllSnapshots (SnapMirror DR)

Nothing

XDP

MirrorAndVault (unified replication)

XDP

XDP

MirrorAndVault (unified replication)

As the table shows, the default policies assigned to XDP in different circumstances ensure that the conversion maintains the functional equivalence of the old types. Of course, you can use different policies as needed, including policies for unified replication:

If you specify…​ And the policy is …​ The result is…​

DP

MirrorAllSnapshots

SnapMirror DR

DP

XDPDefault

SnapVault

DP

MirrorAndVault

Unified replication

XDP

MirrorAllSnapshots

SnapMirror DR

XDP

XDPDefault

SnapVault

XDP

MirrorAndVault

Unified replication

The only exceptions to conversion are as follows:

  • SVM data protection relationships continue to default to DP mode in ONTAP 9.3 and earlier.

    Starting with ONTAP 9.4, SVM data protection relationships default to XDP mode.

  • Root volume load-sharing data protection relationships continue to default to DP mode.

  • SnapLock data protection relationships continue to default to DP mode in ONTAP 9.4 and earlier.

    Starting with ONTAP 9.5, SnapLock data protection relationships default to XDP mode.

  • Explicit invocations of DP continue to default to DP mode if you set the following cluster-wide option:

    options replication.create_data_protection_rels.enable on

    This option is ignored if you do not explicitly invoke DP.