fsid=0 explanation in nfs exports please

glorsplitz · 07-19-2019, 11:01 PM

I had a couple drives I was exporting, I replaced the drives with one drive and have only one export, as in

Quote:

/home/media 192.168.0.0/255.255.255.0(ro,root_squash,no_subtree_check,nohide,fsid=0)

I wanted to try/use UUID in /etc/fstab with this drive

Quote:

UUID=51902cc0-c145-4c2f-9ba7-d522292c63d9 /home/media ext3 defaults 1 2

Code:

showmount -e 192.168.0.20

Quote:

Export list for 192.168.0.20:
/home/media 192.168.0.0/255.255.255.0

Code:

mount -t nfs 192.168.0.20:/home/media /mnt/tmp

resulted in

Quote:

mount.nfs: mount(2): Stale file handle
mount.nfs: Connection timed out

until I added fsid=0 to /etc/exports, I've read what it's supposed to do but it's not clear to me.

https://linux.die.net/man/5/exports

Quote:

fsid=num|root|uuid
NFS needs to be able to identify each filesystem that it exports. Normally it will
use a UUID for the filesystem (if the filesystem has such a thing) or the device
number of the device holding the filesystem (if the filesystem is stored on the
device).

As not all filesystems are stored on devices, and not all filesystems have UUIDs,
it is sometimes necessary to explicitly tell NFS how to identify a filesystem.
This is done with the fsid= option.

For NFSv4, there is a distinguished filesystem which is the root of all exported
filesystem. This is specified with fsid=root or fsid=0 both of which mean exactly
the same thing.

Can someone please explain.

Alien Bob · 07-20-2019, 05:01 PM

Did you re-mount /home/media after editing /etc/fstab, but forgot to also restart the NFS daemons afterwards?

bassmadrigal · 07-20-2019, 05:07 PM

I can't comment on what's wrong, but I do have many nfs exports (just counted and it's at 9!), and I don't include the fsid option on any of them and I've never had issues with mounting them remotely.

Also, a stackexchange answer seems to show this can happen when the client has a folder mounted and the server reboots, without the client unmounting it's share. You might be able to fix it by running the following on the server:

Code:

exportfs -ua
exportfs -a

glorsplitz · 07-20-2019, 06:21 PM

Thank you both for responding.

I rebooted which would mount fstab and start NFS daemons.

Yes I found that stackexchange post and it didn't help.

I had NFS running with several exports from a couple drives and did not need fsid.

With the new drive I'm trying to figure what best to do.

Something to do with NFS using a single drive and single export?

System is up to date.