[ILUG] rsync over ssh problem

[Marcus Furlong]

On Wed, Aug 18, 2010 at 7:00 PM, kevin <lists at cybercolloids.net> wrote:
> Part of our backup routine is a cron job that runs rsync over ssh to an
> offsite computer every night. Recently I have noticed that it fails
> about 1/2 of the time, not always and a failed rysnc one night might
> work fine the next night.
>
> The error we get is:
>
> Write failed: Broken pipe
> rsync: connection unexpectedly closed (13729658 bytes received so far)
> [receiver]
> rsync error: error in rsync protocol data stream (code 12) at io.c(601)
> [receiver=3.0.7]
> rsync: connection unexpectedly closed (783 bytes received so far)
> [generator]
> rsync error: unexplained error (code 255) at io.c(601) [generator=3.0.7]
>
> I have the "KeepAlive Yes" option in the sshd_config file
>
> rsync options used in the batch file are:
>
> rsync -e ssh -avzxHS --numeric-ids --del --delete-excluded
> --exclude-from "/home/cybercolloids/exclusions.txt" --exclude ".gvfs"
>
> Looking at the log file the only thing that looks odd is that the
> connection fails when transferring large image files - a few Mb
>
> Any ideas?

Had the same issue on two different boxes before. Fixed the first one
by disabling TCP Selective Acknowledgement (RFC2018). Apparently there
was router that was buggy in that regard:

   echo 0 > /proc/sys/net/ipv4/tcp_sack

The second time, it was a DSL connection that dropped out when
transferring big files. Diagnosed it by running smokeping and
eventually switched to a different provider.

-- 
Marcus Furlong