When tracking an NFS problem, remember the main points of possible failure: the NFS server, the NFS client, and the network. Try to isolate each component to find the one that is not working. The mountd and nfsd daemons must always be running on the server for remote mounts to succeed.
When the network or server has problems, programs that access hard-mounted remote files fail differently than programs that access soft-mounted remote files. Hard-mounted remote file systems cause the client's kernel to retry the requests until the server responds again. Soft-mounted remote file systems cause the client's system calls to return an error after several attempts. Avoid soft mounting because the errors can result in unexpected application errors and data corruption.
When a file system is hard mounted, a program that tries to access the file system hangs if the server fails to respond. In this situation, the NFS system displays the following message on the console:
NFS server hostname not responding still trying
When the server finally responds, the following message appears on the console:
NFS server hostname ok
A program that accesses a soft-mounted file system whose server is not responding generates the following message:
NFS operation failed for server hostname: error # (error-message)
Caution - Because of possible errors, do not soft-mount file systems with read-write data or file systems from which executables are run. Writable data could be corrupted if the application ignores the errors. Mounted executables might not load properly and can fail.