Causes of slow access times for NFS

If access to remote files seems unusually slow, ensure that access time is not being inhibited by a runaway daemon, a bad tty line, or a similar problem.

Network connections
Use the nfsstat command to gather information about your network connections.
Setting MTU sizes
To set MTU size, use the SMIT fast path, smit chif.
Transmit queue sizes
Communication adapter transmit queue sizes are set with SMIT.
Hung programs
If programs hang during file-related work, the NFS server could have stopped.
Permissions and authentication schemes
Sometimes, after mounts have been successfully established, there are problems in reading, writing, or creating remote files or directories. Such difficulties are usually due to permissions or authentication problems.
Host name resolution on an NFS server
When an NFS server services a mount request, it looks up the name of the client making the request. The server takes the client Internet Protocol (IP) address and looks up the corresponding host name that matches that address.
Limitations on the number of groups in the NFS structure
On systems that use NFS Version 2 or 3, users cannot be a member of more than 16 groups without complications.
NFS servers with earlier versions of NFS
An NFS Version 3 client cannot mount to an NFS Version 4 server.
RPCSEC-GSS problem determination
Consider the following solutions when you are having trouble with RPCSEC-GSS.
EIM problem determination
When troubleshooting EIM, consider the following tips.
Problems that occur if the NFS kernel extension is not loaded
Some NFS commands do not run correctly if the NFS kernel extension is not loaded. Some commands with this dependency are: nfsstat, exportfs, mountd, nfsd, and biod.
Problems that occur if kerberos support is not installed
If kerberos support is not installed, the gssd daemon will not start.
Items to check if the registry daemon is not running
The nfsrgyd daemon will not run if the NFS version 4 domain has not been configured.

Parent topic: NFS troubleshooting