sctp support for rsync?

Wayne Davison wayned at
Sun Mar 5 22:12:57 GMT 2006

On Mon, Mar 06, 2006 at 09:22:04AM +1300, Jason Haar wrote:
> We have fat pipes and yet a single rsync session cannot saturate it
> due to the latency.

Rsync is not adversely affected by high latency connections because the
three processes (generator, sender, and receiver) all run concurrently
without waiting for any round-trip confirmations (until the end of the
entire file list).  If your link isn't being saturated, it should be due
to some other bottleneck, such as disk I/O, CPU, or just not being able
to rapidly find the files that need to be updated.

If disk I/O is the limiting factor, try using --whole-file (i.e. as
your transfer speed approaches/exceeds your disk I/O speed, rsync's
incremental update algorithm can take longer to find the differences
than it would take to just send the updated file).

It also helps to avoid things that laden the CPU, such as the --compress
(-z) option, and slow ssh encryption.  You can try switching ssh to
blowfish encrypt, or perhaps switch from ssh to rsh if CPU is your
limiting factor.


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