strange nfs/rsync stalls

[Gerrit Kühn]

On Wed, 4 Nov 2015 14:43:54 +0100 Gerrit Kühn <gerrit.kuehn at aei.mpg.de>
wrote about strange nfs/rsync stalls:

> I have a couple of other machines that use the same server in the same
> way, none of them ever showed this behaviour. Are there any
> suggestions how to debug/fix this?

Some more pointers from my side: I see a similar issue when using rsync
over ssh, so this does not appear to be a nfs issue. However, even when
running rsync with -vvv and debug turned on, I cannot find any hard reason
for the lockups. They appear to happen erratically, not at a fixed file or
such. When transferring over ssh, I can press CTRL-C to make the syncing
go on until the next lockup happens.
I also tried to swap client and server (i.e., the machine where I start
rsync), and that runs without any issue... which leaves me even more
puzzled. Any hints are still very welcome.


cu
  Gerrit