clnt_control - Linux


clnt_control is a command-line tool used to retrieve and modify runtime properties of Network File System (NFS) clients. It provides a convenient interface for admins and developers to monitor and configure NFS client behavior, enhancing performance and resolving issues.


clnt_control [options] [command]


-h, –help: Display help information
-V, –version: Display version information
-v, –verbose: Enable verbose mode
-s, –socket: Specify the socket to use (default: /var/lib/nfs/rpc_pipefs/nfs)
-p, –port: Specify the port to use (default: 31954)
-t, –timeout: Set the connection timeout in seconds (default: 30)


list: List current NFS client properties
get: Get the value of a specific NFS client property
set: Set the value of a specific NFS client property
unmount: Request unmount of NFS mounts


Get current NFS client properties:

clnt_control list

Get the value of the readahead property:

clnt_control get readahead

Set the tcp_keepalive property to 1:

clnt_control set tcp_keepalive 1

Request unmount of NFS mounts:

clnt_control unmount

Common Issues

Connection refused error:

  • Ensure the NFS client service is running.
  • Verify the port specified with -p is correct.
  • Check if there are any firewall rules blocking the connection.


Monitor NFS client performance:

watch clnt_control list --verbose

Automatically set tcp_keepalive property on boot:
Create a systemd service unit:

Description=Set NFS client TCP keepalive property

ExecStart=/usr/sbin/clnt_control set tcp_keepalive 1


Related Commands

  • nfsstat: Provides statistics about NFS server performance
  • nfsstatd: Exports NFS server statistics for remote monitoring
  • mount: Mounts and unmounts filesystems, including NFS mounts
  • exportfs: Manages NFS exports on the server side