Search Current Space

compared with
Current by David Wartell
on Sep 16, 2009 08:27.

This line was removed.
This word was removed. This word was added.
This line was added.

Changes (1)

View Page History
After the Initial Replica the process is very different form the other methods.  Every time a backup job is run a Synchronization is performed.  During the synchronization process a point-in-time snapshot of the Disk Volume is created and Deltas are computed based on the last completed synchronization.  The Deltas are block level and are usually computed at a level below the file system very close to the raw disk structure.  These deltas represent the low level changes to the disk volume made since the last recovery point. 

A Recovery Point appears like a Full backup to the user.  That is only in appearance as each recovery point only contains block level Deltas or changes since the last Synchronization.  The method for computing deltas can vary in implementation.  R1Soft uses a near-Continuous Delta method described here *FIXME LINK TO CDP TECH DOC*.  [Computing Deltas - near-Continuous (CDP)].  Deltas could potentially be computed by comparing all disk volume blocks every synchronization however this would be undesirable due to the time needed to do the comparison and heavy impact on disk I/O.