Carlos Carvalho carlos at
Tue May 17 11:46:12 MDT 2011

Matt McCutchen (matt at wrote on 17 May 2011 12:50:
 >On Tue, 2011-05-17 at 08:45 -0700, CACook at wrote:
 >> The connexion is Gb enet end-to-end, and is running at only 40Mb/s.
 >> It has far more capacity than that.  The only limiting factor I can
 >> see is on the backup server one core of the CPU is running 100% rsync.
 >> Clearly rsync is not multi-threaded.
 >That's probably the delta-transfer algorithm.

Yes. And what's important is not the net flux, it's the transfer rate,
which can be a lot higher if there are few changes.

You might want to check the read rate at the server, it should be
in the hundreds of MB/s. If not rsync got stuck somewhere.

Multi-threading rsync is of little use because the the bottleneck will
be the disk IO.

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