rsync (or rsync-like tool) provides local metadata cache ?

[Johannes Totz]

On 30/09/2011 00:57, Jason Usher wrote:
> Let's say I have a slow, or high latency (or both) link between two
> hosts, and transferring data is expensive.
> 
> Is it possible with rsync (or any other tool like rsync) to maintain
> a local metadata cache, such that I can rsync without transferring
> data to and from the hosts about what files are already in place ?
> 
> That is, I already "know" what is out there and don't need to check
> anything - I can just use the state information on the sending end to
> send only the data required, and don't need to traverse the remote
> filesystem for sizes/datestamps/hashes/etc.
> 
> Does this exist ?

Check out the checksum database patches. Maybe these could help in your
case...