[CentOS] nfs4 problem in CENTOS6

Thu Nov 17 14:43:54 UTC 2011
Michael Schumacher <michael.schumacher at pamas.de>


This is slightly offtopic, but I have been trying to resolve that problem for two days now without much success. It looks like this may be something that works with CENTOS5, but not with CENTOS6!

I have two machines, fileserver1 and server5.
fileserver1 runs on CENTOS6 (virtualized, if this is important), server5 runs on Centos5. Both are running with the most recent updates.

Server5 is a machine to store backups on. Several servers, including fileserver1, are mounted with nfs4 on server5.

fileserver1 has this /etc/fstab:

UUID=73254e19-895f-4190-b2e3-13a2b0bec9ce /     ext4    defaults        1 1
UUID=ac658802-73e4-4c87-bb03-6f9af1ebc4f8 /mnt/data ext4    defaults        1 2
UUID=4836335a-2d66-4d12-9dec-7197dc772d77 swap  swap    defaults        0 0
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/mnt /mnt dazukofs
/                       /nfsexport/root         none    bind            0 0
/mnt/data               /nfsexport/data         none    bind            0 0

AS you can see, /mnt/data is a partition mounted below /.

I am binding both partitions to /nfsexport/... and export them in /etc/exports with 

/               server*.pamas.local(ro,secure,no_root_squash,crossmnt,fsid=0)
/mnt/data       server2.pamas.local(ro,secure,no_root_squash,nohide) server5.pamas.local(ro,secure,no_root_squash,nohide)

If I execute
[root at server5 ~]# /etc/init.d/nfs reload

I get 

exportfs: /mnt/data does not support NFS export
exportfs: /mnt/data does not support NFS export

on the console, but nothing in the log-files.

On server5, I entered

[root at server5 ~]# mount -t nfs4 /mnt/nfs/fileserver1/root

successfully and

[root at server5 ~]# mount -t nfs4 /mnt/nfs/fileserver1/data


mount: pinging: prog 100003 vers 4 prot tcp port 2049

and hangs. 

ctrl-c returns me to the prompt, but /mnt/data is not mounted.

The active mount /mnt/nfs/fileserver/root is working nicely, but if I cd into /mnt/nfs/fileserver/root/mnt and enter ls there, the console hangs infinetly. 

As I wrote, server5 also mounts other servers filesystems without problems. All working systems are CENTOS5, the one not working is CENTOS6.

Any idea?

best regards
Michael Schumacher