Is there a standard for remote backup file change detection?

I'm going to have a need for an efficient remote change detection algorithm for backup of an ordinary filesystem.

The files are backed up to a remote machine a开发者_运维技巧nd bandwidth is at a premium, so it's going to be difficult to compare files. I've looked into Remote Differential Compression and rsync, but I don't know which direction I should go from here. Which is more bandwidth efficient? What does commercial backup software do? Is there a standard algorithm everyone uses?

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I found two very good articles on this:

Remote File Synchronization Single-Round Algorithms explains and compares leading methods very helpfully.

Algorithms for Low-Latency Remote File Synchronization goes into lots of technical detail on remote file synchronization based on set reconciliation techniques.