VVR also enables you to take instant space-optimized snapshots. Unlike instant full snapshots, the instant space-optimized snapshots require less storage space than the original volume because space-optimized snapshots store only the data that has changed between the original volume and the snapshot. Typically, the data that has changed between the original volume and the snapshot volume over the lifetime of the snapshot is minimal compared to the total data on the volume. Thus, the space-optimization achieved can be significant.

The snapshot data is managed by VVR using a cache object which functions as a space-optimized persistent store. You must create the cache object before you take the instant space-optimized snapshots or specify the size of the cache object. Multiple snapshots can be created on the same cache object. The cache object can be created with an autogrow option set to on to allow it to grow automatically if the cache volume size is not enough for the specified writes. When preparing the RVG volumes for the snapshot operation, create the cache object.