Various embodiments of systems and methods are disclosed for tracking
valid regions of a working volume. State information identifies which
regions of the working volume are currently valid. When the volume is
created, the state information can be initialized to a value that
identifies all regions of the volume as being invalid. The invalid
regions do not need to be synchronized, since there will not be any need
to reconstruct the data within those regions to a particular value.
Accordingly, volume initialization, which synchronizes redundant data
(e.g., RAID parity or a mirrored copy) with application data in the
invalid regions, can be delayed. As the volume is accessed by an
application, the redundant data associated with the regions being
accessed is synchronized, and the state information is updated to
indicate that those regions are valid.