[Gluster-users] Hanging writes after upgrading "clients" to debian squeeze

[Brian Candler]

On Sun, Feb 05, 2012 at 09:49:47PM +0100, Stefan Becker wrote:
> - no ip tables involved

OK. So how about this on the client:

tcpdump -i eth0 -nn host 10.10.100.40 or host 10.10.100.41

(replace eth0 as necessary)

That will show you traffic to and from the bricks. When you issue a write
(e.g. touch /path/to/foo), does traffic only go out to one brick? Do you
see any TCP retransmissions? Does 'netstat -nt' show TCP connections to both
bricks? Does Send-Q stay at zero most of the time, or is it stuck at a
non-zero value?

You could also try:
  strace -p <pid-of-glusterfs-process>
on the client as well. You should see writev(fd,...) and readv(fd,...) with
different fds for communication to each of the bricks. Then try issuing
a single write.

The strace output may not tell you much by itself, but if you compare what
you see on a non-upgraded (working) client versus an upgraded (broken)
client, you might be able to see what it's getting stuck on.

Regards,

Brian.