This shows you how to troubleshoot NFS issues properly for debian-based systems
- Error: Can't read superblock
- In order to mount a NFS network file system, it is necessary to run the portmapper on the client computer. An error may occur, if an attempt is made to mount a NFS network file system without the local portmapper running:
mount scooby:/foobar /nfs/scooby/foobar mount: scooby:/foobar Can't read superblock
mount.nfs: rpc.statd is not running but is required for remote locking :: This error occurs if the portmapper has not been started on the client machine.
NFSv4 Problems with uid/gid not synchronizing properly
Make sure that you have access to port 2049 from the client to the server (hint: telnet my.nfs.example.com 2049). If no firewalls are blocking your traffic, then proceed to make sure that you add an "actimeo" option to your nfs client like the following:
Example: nfs client
$> cat /etc/auto.master /mnt/auto /etc/auto.nfs --timeout=60 $> cat /etc/auto.nfs backup -fstype=nfs4,rw,rsize=32768,wsize=32768,timeo=14,intr,actimeo=10,20,10,20 my.nfs.example.com:/backup
See man nfs for more on what "actimeo" means.
my.nfs.example.com server is configured using the following lines:
Example: nfs server
# /etc/exports: the access control list for filesystems which may be exported # to NFS clients. See exports(5). /mnt/shared *.example.com(rw,fsid=0,no_subtree_check,insecure,sync,crossmnt) /mnt/shared/tmp *.example.com(rw,no_subtree_check,insecure,sync) /mnt/shared/backup box1.example.com(no_subtree_check,rw,sync,insecure,no_root_squash) box2.example.com(no_subtree_check,rw,sync,insecure,no_root_squash)