How do you force unmount a hung NFS share?

You can use umount -f -l /mnt/myfolder , and that will fix the problem.

Table of Contents

-f – Force unmount (in case of an unreachable NFS system). (Requires kernel 2.1.
-l – Lazy unmount. Detach the filesystem from the filesystem hierarchy now, and cleanup all references to the filesystem as soon as it is not busy anymore.

How do I permanently mount NFS?

How to Mount an NFS File System ( mount Command)

Become superuser or assume an equivalent role.
Create a mount point for the file system to be mounted, if necessary. # mkdir /mount-point.
Ensure that the resource (file or directory) is available from a server.
Mount the NFS file system.

Can you share an NFS share?

Network File Sharing (NFS) is a protocol that allows you to share directories and files with other Linux clients over a network. Shared directories are typically created on a file server, running the NFS server component. Users add files to them, which are then shared with other users who have access to the folder.

How do you check if NFS share is mounted?

Use the showmount command to display the remote NFS server mount information. If you omit the options, the default option displays hostnames of all remote mounts from the hostname NFS server. If you omit the hostname parameter, then the local hostname is used.

How do I clear stale in NFS mounts?

How do I fix this problem? First command (umount) forcefully unmount a disk partition /mnt/local (NFS). (b) Or try to mount NFS directory with the noac option.

What is lazy umount?

Lazy umount is a regular umount, which happens in background. In addition is hides the mount entry, which makes it looks like umount have worked (or Detach the filesystem from the file hierarchy , how man page says). In really the unmount will happen when filesystem is not in use anymore.

How do I troubleshoot NFS mount issue?

Solution

Ensure that the NFS server is running correctly on all of the CES nodes and that the CES IP address used to mount is active in the CES cluster.
Ensure that the firewall allows NFS traffic to pass through.
Verify that the NFS client is allowed to mount the export.

What ports are needed for NFS?

Network File System (NFS) is used by UNIX clients for file access. NFS uses port 2049. NFSv3 and NFSv2 use the portmapper service on TCP or UDP port 111.

Is NFS faster than SMB?

Reading transactions are faster in SMB when compared with NFS. The reading transaction rate is 4 MB. Write transactions are slower than read transactions, and the rate is 0.128 MB. Write transactions are relatively slow but faster when compared with NFS.

Is NFS the same as SMB?

Both SMB and NFS are client-server communication protocols used for sharing data over a network. SMB is best for Windows file sharing whereas NFS is ideal for Linux-based environments. SMB is, however, more secure than NFS in terms of data security.

How do I check NFS mount connectivity?

How to Check Connectivity on an NFS Client

On the client, check that the NFS server is reachable.
If the server is not reachable from the client, ensure that the local name service is running on the client.
If the name service is running, ensure that the client has received the correct host information.

What causes stale NFS mounts?

The answer is any change in the mounted file’s underlying inode, disk device, or inode generation on the NFS server causes an NFS stale filehandle.

How do you know if NFS is stale?

every once in a while I’m unable to load my server URL due to stale NFS (diagnosed after the fact). Stale files are usually found using ls -ltR /<mounted directory path> | grep “\?” , but this usually takes some time (since it goes over all files in a given path).

What is MNT in Linux?

This is a generic mount point under which you mount your filesystems or devices. Mounting is the process by which you make a filesystem available to the system. After mounting your files will be accessible under the mount-point.

How do I umount in Linux?

To unmount a mounted file system, use the umount command. Note that there is no “n” between the “u” and the “m”—the command is umount and not “unmount.” You must tell umount which file system you are unmounting. Do so by providing the file system’s mount point.

How do I fix mount issue in Linux?

Troubleshooting NFS Mount Issues in Linux

Install the required nfs packages if not already installed on the server # rpm -qa | grep nfs-utils. # yum install nfs-util.
Use the mount command to mount exported file systems.
Update /etc/fstab to mount NFS shares at boot time.

Does NFS use TCP or UDP?

All versions of NFS can use Transmission Control Protocol (TCP) running over an IP network, with NFSv4 requiring it. NFSv2 and NFSv3 can use the User Datagram Protocol (UDP) running over an IP network to provide a stateless network connection between the client and server.

Do I need port 111 for NFS?

Portmapper service is required to run NFS both on the client and the server-side. It runs on Port 111 for both TCP and UDP protocols.

Is NFS multithreaded?

In OneFS, the NFS server is fully optimized as a multi-threaded service running in user space instead of the kernel.

Should I use NFS or Samba?

NFS offers better performance and is unbeatable if the files are medium-sized or small. For larger files, the timings of both methods are almost the same. In the case of sequential read, the performance of NFS and SMB are almost the same when using plain text. However, with encryption, NFS is better than SMB.

Is NFS slower than SMB?

For larger files, the performance of both protocols is similar. Performance of NFS and SMB in the case of sequential reading is similar when using plain texts. But with encryption, NFS is slightly ahead of SMB. In random read, NFS and SMB fare equally with plain text.

Is NFS faster than SSH?

For access of large files over the network, NFS is of course much faster than anything with an SSH transport.

How can I tell if NFS is working?

To verify that NFS is running on each computer:

AIX® operating systems: Type the following command on each computer: lssrc -g nfs The Status field for NFS processes should indicate active .
Linux® operating systems: Type the following command on each computer: showmount -e hostname.

How check stale NFS mount?

Here timeout is a utility that will run the command in the background, and will kill it after a given time, if no SIGCHLD was caught prior to the time limit, returning success/fail in the obvious way. In English: Parse the output of mount , check (bounded by a timeout) every NFS mount point.

How do I permanently mount in Linux?

Mounting Drives Permanently using fstab. The “fstab” file is a very important file on your filesystem. Fstab stores static information about filesystems, mountpoints and several options that you may want to configure. To list permanent mounted partitions on Linux, use the “cat” command on the fstab file located in /etc …

How do you force unmount a hung NFS share?