An aggregate Snapshot copy is a point-in-time, read-only image of an aggregate. You use aggregate Snapshot copies when the contents of an entire aggregate need to be recorded.
An aggregate Snapshot copy is similar to a volume Snapshot copy, except that it captures the contents of the entire aggregate, rather than any particular volume. Also, you do not restore data directly from an aggregate Snapshot copy. To restore data, you use a volume Snapshot copy.
If you use SyncMirror or MetroCluster functionality and you need to break the mirror, an aggregate Snapshot copy is created automatically before breaking the mirror to decrease the time it takes to resynchronize the mirror later. You should not schedule or manually create aggregate Snapshot copies for a mirrored aggregate. These Snapshot copies compete with the SyncMirror baseline Snapshot copies for the aggregate's Snapshot reserve; insufficient Snapshot reserve could prevent a level-1 resynchronization operation from being completed successfully.
If the aggregate file system becomes inconsistent, aggregate Snapshot copies can be used by technical support to restore the file system to a consistent state. If that is important to you, you can ensure that automatic aggregate Snapshot copy creation is enabled. However, disabling automatic aggregate Snapshot copy creation and keeping your aggregate Snapshot reserve at 0 percent increases your storage utilization, because no disk space is reserved for aggregate Snapshot copies. Disabling automatic aggregate Snapshot copy creation and setting the aggregate Snapshot reserve to 0 percent does not affect normal operation, except for making more free space available for data.
For more information about Snapshot copies, see the Data ONTAP Data Protection Online Backup and Recovery Guide for 7-Mode.