Table of ContentsView in Frames

Supported three-hop cascade configurations for SnapMirror

Only certain combinations of SnapMirror replication types are supported for three-hop cascade configurations.

Cascades of three SnapMirror relationships whose first relationship is a synchronous SnapMirror relationship are supported on Data ONTAP 7.1.2 and 7.2.1 releases, and later releases.

The following table lists the three-hop cascade configurations that are supported for SnapMirror replication:

System A to system B System B to system C System C to system D
Synchronous SnapMirror Asynchronous volume SnapMirror Asynchronous volume SnapMirror
Synchronous SnapMirror Asynchronous volume SnapMirror Qtree SnapMirror
Asynchronous volume SnapMirror Asynchronous volume SnapMirror Asynchronous volume SnapMirror
Asynchronous volume SnapMirror Asynchronous volume SnapMirror Qtree SnapMirror
Asynchronous volume SnapMirror Qtree SnapMirror Asynchronous volume SnapMirror
Qtree SnapMirror Asynchronous volume SnapMirror Asynchronous volume SnapMirror

Sample cascade setup

The following diagram depicts the series of cascading volume destinations:
Copying data between storage systems in a cascade configuration

To support the configurations depicted in the preceding diagram, the entries in the /etc/snapmirror.conf file in each of the systems is the cascade should be similar to the following entries: systemA:vol1 systemB:vol1 - 15 * * 1,2,3,4,5systemA:vol1 systemL:vol1 - 15 * * 1,2,3,4,5systemB:vol1 systemC:vol1 - 25 * * 1,2,3,4,5systemC:vol1 systemD:vol1 - 35 * * 1,2,3,4,5systemL:vol1 systemM:vol1 - 25 * * 1,2,3,4,5systemM:vol1 systemX:vol1 - 35 * * 1,2,3,4,5systemM:vol1:systemN:vol1 - 35 * * 1,2,3,4,5systemX:vol1 systemY:vol1 - 45 * * 1,2,3,4,5systemX:vol1 systemZ:vol1 - 45 * * 1,2,3,4,5
Note: When specifying the destination update schedule in the snapmirror.conf file, you should stagger the update times instead of starting multiple destination updates at the same time. If SnapMirror does not have enough resources to perform all scheduled destination updates, it postpones some updates. As a result, SnapMirror might need to perform subsequent updates at times that are different from those you specify in the snapmirror.conf file.