The PerfectRebuild feature is an innovative approach to rebuilding a RAID array in order to significantly reduce the amount of time needed for completion. 

This frees up CPU resources more quickly to be available for I/O and other demands.

PerfectRebuild ignores any portion of the logical drive where no write changes have occurred, focusing only on the parts that have changed. 

The conventional approach has been to rebuild the entire logical drive, even sections with no write changes. 

This reduction in the total time needed for a rebuild is especially signi cant for very large drives. 

 It does this by keeping metadata of the logical drive to track writes to it.

In a normal rebuild, the entire logical drive is rebuilt, even if there’s only 1 file in the logical drive. This takes the same amount of time (hours) no matter how full or empty the Logical Drive is.

Perfect Rebuild keeps track of which blocks of the Logical Drive have ben written to and only rebuilds the parts of the Logical Drive that have been written to, reducing the rebuild time.