Linux NFS Troubleshooting: Difference between revisions

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</blockquote>
</blockquote>


=Verbose <tt>mount</tt>=
=List Filesystems Mounted by a NFS Client=


Try to mount with -v (verbose)
<blockquote style="background-color: #f9f9f9; border: solid thin lightgrey;">
:[[Mount#List_Filesystems_Mounted_by_a_NFS_Client|<tt>mount</tt>: list filesystems mounted by a NFS client]]
</blockquote>


=showmount=
=Useful Commands=


Use
<blockquote style="background-color: #f9f9f9; border: solid thin lightgrey;">
 
:verbose mount <tt>[[Mount#-v|mount -v]]</tt>
<pre>
:<tt>[[showmount]]</tt>
showmount -e
:<tt>[[rpcinfo]]</tt>
</pre>
:<tt>[[exportfs]]</tt>
 
</blockquote>
on the server to see what is exported.


=Failures=
=Failures=
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mount.nfs: mount(2): No route to host
mount.nfs: mount(2): No route to host
</pre>
</pre>
This error means that the NFS client host is not getting a TCP/IP ACK back from the NFS server.
The problem went away after configuring <tt>[[iptables]]</tt> to allow all outbound traffic (see [[Iptables#iptables_Service_Configuration|<tt>iptables</tt> Service Configuration]]).
==<tt>mount(2): Permission denied</tt>==
<tt>mount -v</tt> yields:
<pre>
mount -v -t nfs 192.168.1.4:/volume3/dropbox /mnt/tmp
...
mount.nfs: mount(2): Permission denied
mount.nfs: access denied by server while mounting 192.168.1.4:/volume3/dropbox
</pre>
The error is paired with the following on the server-side:
<pre>
Aug 21 01:35:58 RackStation mountd[11206]: refused mount request from 192.168.1.9 for /volume3/dropbox (/volume3/dropbox): unmatched host
</pre>
The root cause was the fact 192.168.1.9 was not specifically allowed access in the server's [[/etc/exports|<tt>/etc/exports</tt>]].
==<tt>mount: wrong fs type, bad option, bad superblock on ...</tt>==
mount: wrong fs type, bad option, bad superblock on 192.168.1.4:/volume1/nfstest,
      missing codepage or helper program, or other error
      (for several filesystems (e.g. nfs, cifs) you might
      need a /sbin/mount.<type> helper program)
Usually caused by the fact that the client libraries have not been installed. Fix it by [[Linux_NFS_Installation#Install_Client_Packages|installing client packages]].
==<tt>fcntl() failed with file ...: No locks available</tt>==
{{Internal|Docker_Storage_Operations#NFS_Volume_Troubles|Docker Storage Operations - NFS Volume Troubles}}

Latest revision as of 04:02, 21 May 2018

Internal

List Filesystems Exported by a NFS Server

exportfs: list filesystems exported by a NFS server

List Filesystems Mounted by a NFS Client

mount: list filesystems mounted by a NFS client

Useful Commands

verbose mount mount -v
showmount
rpcinfo
exportfs

Failures

mount hangs

I've seen cases when trying to mount a filesystem from other machine hangs if nfs is not started on that machine (service nfs start).

mount.nfs: access denied by server while mounting

I've also seen cases when I get the following error message when not using -t nfs, so use -t nfs:

mount.nfs: access denied by server while mounting f01:/opt/shared

mount(2): No such file or directory

mount -v yields:

mount.nfs: trying text-based options 'bg,vers=4,addr=172.31.20.184,clientaddr=172.31.21.24'
mount.nfs: mount(2): No such file or directory
...

I get this because I use the wrong exported path in /etc/fstab.

mount(2): No route to host

mount -v yields:

mount -v -t nfs 192.168.1.2:/volume3/dropbox /mnt/tmp
mount.nfs: timeout set for Sun Aug 21 00:44:48 2016
mount.nfs: trying text-based options 'vers=4,addr=192.168.1.2,clientaddr=192.168.1.9'
mount.nfs: mount(2): No route to host

This error means that the NFS client host is not getting a TCP/IP ACK back from the NFS server.

The problem went away after configuring iptables to allow all outbound traffic (see iptables Service Configuration).

mount(2): Permission denied

mount -v yields:

mount -v -t nfs 192.168.1.4:/volume3/dropbox /mnt/tmp
...
mount.nfs: mount(2): Permission denied
mount.nfs: access denied by server while mounting 192.168.1.4:/volume3/dropbox

The error is paired with the following on the server-side:

Aug 21 01:35:58 RackStation mountd[11206]: refused mount request from 192.168.1.9 for /volume3/dropbox (/volume3/dropbox): unmatched host

The root cause was the fact 192.168.1.9 was not specifically allowed access in the server's /etc/exports.

mount: wrong fs type, bad option, bad superblock on ...

mount: wrong fs type, bad option, bad superblock on 192.168.1.4:/volume1/nfstest,
      missing codepage or helper program, or other error
      (for several filesystems (e.g. nfs, cifs) you might
      need a /sbin/mount.<type> helper program)

Usually caused by the fact that the client libraries have not been installed. Fix it by installing client packages.

fcntl() failed with file ...: No locks available

Docker Storage Operations - NFS Volume Troubles