Additional restrictions and limitations

11/20/2020 Contributors Download PDF of this page

There are several additional restrictions and limitations when using the SnapMirror Business Continuity solution.

Consistency groups

The maximum number of SnapMirror Synchronous consistency group relationships in a cluster is five, a limit which is platform-independent. If you reach or attempt to exceed this limit, the following message is displayed:

The number of SnapMirror Synchronous consistency group relationships in a cluster cannot exceed 5

Volumes per consistency group

The maximum number of volumes supported per SnapMirror Synchronous consistency group relationship is twelve, a limit which is platform-independent. If you reach or attempt to exceed this limit, the following message is displayed:

The number of volumes in a SnapMirror Synchronous Consistency Group cannot exceed 12

Volumes

The limit is on the number of endpoints and not the number of relationships. A consistency group with 12 volumes contributes 12 endpoints on both the source and destination.A SnapMirror Synchronous relationship with both source and destination volumes on the same HA pair contributes 2 endpoints.

The maximum endpoints per platform are included in the following table.

S. No	Platform	Endpoints per HA for SM-BC	Overall sync and SM-BC endpoints per HA
1	AFF	60	80
2	ASA	60	80

SAN object limits

The following SAN object limits are included in the following table and apply regardless of the platform.

Limits of objects in an SM-BC relationship	Count
LUNs per volume	256
LUN maps per node	2048
LUN maps per cluster	4096
LIFs per VServer (with at least one volume in an SM-BC relationship)	256
Inter-cluster LIFs per node	4
Inter-cluster LIFs per cluster	8