A SyncMirror aggregate has two plexes. This setup provides a high level of data availability because the two plexes are physically separated.
Physical separation of the plexes protects against data loss if one of the shelves or the storage array becomes unavailable. The unaffected plex continues to serve data while you fix the cause of the failure. Once fixed, the two plexes can be resynchronized.
Another advantage of mirrored plexes is faster rebuild time.
In contrast, if an aggregate using SnapMirror for replication becomes unavailable, you can use one of the following options to access the data on the SnapMirror destination (secondary):
However, you can manually set the SnapMirror destination to allow read/write access to the data.
An aggregate that is mirrored using SyncMirror requires twice as much storage as an unmirrored aggregate. Each of the two plexes requires an independent set of disks or array LUNs. For example, you require 2,880 GB of disk space to mirror a 1,440-GB aggregate—1,440 GB for each plex of the mirrored aggregate.