MirrorView has many different states it can be in. Here is a list (I got this from Help in Navisphere):

states ¿ There are two types of states: remote mirror states and image states. The remote mirror states are Active and Attention. The image states are Synchronized, Consistent, Synchronizing, Out-of-Sync, and Rolling Back. They describe the data on the secondary storage system in relation to the data on the primary storage system.

Synchronized state ¿ The state in which the data in the secondary image is identical to that in the primary. On the next write to the primary, the image state will change to Consistent. Also see states.

Synchronizing state ¿ A secondary image in the process of synchronization. The data in the secondary image is not usable for recovery until the synchronization operation completes. Thus, you cannot promote an image in the Synchronizing state to the primary image. Once initial synchronization completes, a MirrorView/A mirror should not return to this state, but stay consistent or synchronized.

Out-of-Sync state ¿ A remote mirror image state in which the software does not know how the primary and secondary images differ; therefore, a full synchronization is required to make the secondary image(s) usable for recovery.

Consistent state (of an image) ¿ State in which a secondary image is identical to either the current primary image or to some previous (consistent point-in-time) instance of the primary image.

rolling back state ¿ The state that occurs after a successful promotion where there was an unfinished update to the secondary image. This state persists until the Rollback operation completes

-Ryan