Help me with this Questiions

[Harish]

I would like to understand the capabilities of GNU rsync software /
utility. This is used for syncing file systems / file level data across
two systems. I specifically would like to know its capabilities in
syncing files – 

 
1)  How does it replicate data changes to  files – entire file or only
the incremental blocks? 

2) Does it have any block level replication capabilities?

3) Can it replicate files while the file is in open state (oracle redo
log file)? This is particularly a problem in windows environment,
typically.