RE Nonresponsive NFS mounts

[Adrian Jujescu]

Hello All,

On a HP-UX 11.11i machine I NFS mount a volume exported from a SUN machine.
I have a strange problem with that volume:
- from time to time the volume frozen. The cd, ls, fuser -cu, umount, fuser -ck commands fails. I issue the commands and the session prompt dissapear and never comeback. The terminal session is locked and there is no method to recover. The single method to unmount the NFS volume is to reboot the workstation.

I have 2 questions:
1. Do you know a method to unmount/remove the NFS volume WITHOUT rebooting the workstation and without using the umount, fuser -ck calls which as I say previously fail ?
2. There are some precautions, parameters which must be set on the HP-UX machine when yu mount NFS volumes exported from SUN machines ?

[Ravi_8]

Hi

is there any network brakes?

[Adrian Jujescu]

Hello,

There are no problems with the network connection. On the same machine are mounted different NFS volumes from other HP-UX machines and I dont have any problem like the a/m one.

[Ravi_8]

Hello

1. check /etc/fstab file, if NFS entries for that machine(sun) exist, comment the line and issue the command
#mount -a

2. No precautions to NFS mount the file system from sun machine.but the NFS client daemons must be running (ps -aef|grep -i nfs). statd and lockd daemons must also be running for the NFS (check /etc/rc.config.d/nfsconf file for NFS_CLIENT flag. restart the NFS services /sbin/init.d/nfs.client stop/start)

[Florian Heigl (new acc)]

There must be some nfs/network issues, otherwise the nfs-mount would not hang.

You should see messages in /var/adm/syslog/syslog.log refering to a non-responding nfs server.

To ease up the issue a bit, You can 'background' the nfs mount by adding 'bg' to the parameters for it in /etc/fstab.

otherwise You should search into the issue, but right know I don't remember the command for the nfs status informations - maybe someone can add this information?

[Stephen Keane]

nfsstat misght come in useful :)

[Florian Heigl (new acc)]

thanks stephen - I missed the second 's' - time for another coffee :)

[Bill Hassell]

If you get the latest NFS patches and dependencies, you may be able to force a umount. The problem with forcing a umount is that you are ripping out a filesystem from HP-UX that may have users cd'ed into the directory (never a good idea for NFS), programs have files open on the NFS mount point, etc. NFS is a faierly fragile filesystem, especially when it is shared on a wide open network (populated with lots of PCs, Macs, Novell, Linux, etc).

fuser just doesn't have enough code in it to accurately identify all the processes that must be killed to free an NFS mount. You need a copy of lsof from http://hpux.connect.org.uk/ to find all the processes.

It's important to look at nfsstat to see if biod and nfsd processes need to be increased. Dave Olker's book on NFS is invaluable (if not scary) in understanding how NFS should be configured and what limitations exist.