Is it possible to use rsync daemon running on 64-bit machine from a 32-bit machine?

Chris Green cl at
Tue Jun 4 11:17:15 UTC 2024

Paul Slootman via rsync <rsync at> wrote:
> On Sun 02 Jun 2024, Chris Green via rsync wrote:
> > I have an rsync daemon running on a 64-bit (x86_64) system which I
> > successfully use for backups from several other 64-bit systems on my
> > LAN.
> > 
> > I want to use it for backups from a BeagleBone Black (32-bit, armv7l)
> > but it fails as follows:-
> > 
> >     root at bbb:~# rsync -a /etc chris at backup::bbb
> >     Password: 
> >     pre-xfer exec returned failure (256)
> >     rsync error: requested action not supported (code 4) at
> >     clientserver.c(1171) [Receiver=3.2.7]
> >     rsync: [sender] read error: Connection reset by peer (104)
> >     root at bbb:~# 
> > 
> > Is it simply not possible to do what I'm trying to do or is there some
> > way to tell the rsync daemon to work with connections from 32-bit
> > clients?
> There should be no problem communicating between 32-bit and 64-bit
> systems with rsync.
> Make sure that the versions of rsync aren't too different, you may run
> into problems with rsync options not being supported on the old one.
> The error message says that there was a problem with the pre-xfer exec.
> Check what that's doing (in the daemon's rsyncd.conf), most probably
> that is the problem.
Yes, I saw that the error is in the 'pre-xfer exec' but it's exactly
the same as works with all the 64-bit clients.  I.e. it's the same
rsyncd and configuration on the server.

.... after a lot of digging around I found the problem.  The first
pass of the pre-xfer exec generates a warning error message which was
failing because it was trying to send it to a system that no longer
exists.  The 64-bit/32-bit difference was a red herring, it was just
that the 64-bit systems had been doing backups for a while so didn't
generate any error messages (and so no mail failures).

Thanks for making me dig further! :-)

Chris Green

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