Date: 2002-07-30

Description: Certain NFS-exported files become unreadable by the cluster nodes.

Affects: Front-end PCs running the Linux 2.4.x kernel and using the ext3 filesystem (e.g., RedHat 7.x)

Summary: Hard-linked files on the front-end PC, and possibly other types of files, that
are exported by the front-end PC to the nodes using NFS can become unreadable
by the cluster nodes. This can cause many applications to fail to run on the
cluster, often resulting in "Stale NFS File Handle" errors.

Symptoms: "Stale NFS File Handle" error reported when trying to run applications on the cluster.

Diagnostic test: Inspect the /var/log/messages file on the front-end PC and the
cluster nodes and look for lines reporting the error 
"kernel: nfsd Security: xxx bad export,"
where 'xxx' is a file name such as .ssh/identity.pub.
If you see a message like this, proceed as outlined below.


Solution: The following procedure must be performed by the root user.

Step 1. Modify the /etc/exports file on the front-end PC to include the
option "no_subtree_check" for every directory exported to the cluster. Use the
following example as a guide:

# Begin modification made by ./setup from ROCKETCALC on 2002-06-06 08:26:08
/usr   192.168.55.0/255.255.255.0(rw,no_subtree_check,no_root_squash,insecure)
/lib   192.168.55.0/255.255.255.0(ro,no_subtree_check,no_root_squash,insecure)
/home  192.168.55.0/255.255.255.0(rw,no_subtree_check,no_root_squash,insecure)
# End modification made by ./setup from ROCKETCALC on 2002-06-06 08:26:08

Step 2. Completely restart the NFS service on the front-end PC with the 
commands:
/etc/rc.d/init.d/nfs stop
/etc/rc.d/init.d/nfs start

Step 3. Reboot the cluster nodes.