rsync hangs, leaves defunct process

[David Mann]

Hello,

I'm experiencing a weird problem which I haven't been able to track down 
for 8+ weeks now.

Situation is as follows: There is a nigthly backup from our main server 
to a backup server. The server base directory is mounted there read-only 
via NFS. Then we do something like this:

1. Duplicate the contents of yesterday's backup into
    /sicherungen/2007/02/02/01.41/
2. Rsync the server directory against that with the following command:

rsync -va --delete --timeout=180 --no-detach /server_ro/ 
/sicherungen/2007/02/02/01.41/

[I've added the --timeout and --no-detach opitons for testing.]

Now, this usually works for a few days, then rsync hangs, leaving a 
defunct process:

root     30729 30695  0 01:55 ?        00:00:02 rsync -va --delete 
--timeout=180 --no-detach /server_ro/ /sicherungen/2007/02/02/01.41/
root     30730 30729  0 01:55 ?        00:00:00 [rsync] <defunct>

The last thing the log says is: "building file list ..."

Since the processes seem not to be killable, the only "remedy" is to 
reboot the backup- server. Then it will work for a few days, until it 
hangs again.

Installed are two SuSE 9.3 EE Linuxes, both fully updated. I'm not sure 
which kernel versions, but both shóuld be 2.6.x I think. If that is 
important please tell me how I could provide you with that information.

BTW it's "rsync  version 2.6.3  protocol version 28"

I'm kind of lost here, and not exactly into Linux. I would appreciate 
any help.

Kind Regards,
David