Data copied via NFS is invisible & doesn't use space in a dataset

[kiler129]

I think I did something dumb while playing with my TrueNAS SCALE installation. After installation I created a radidz pool with standard settings. Then I created two datasets:

Code:

root@truenas[/mnt/vault]# ls -R -aslh /mnt/vault
/mnt/vault:
total 2.0K
512 drwxr-xr-x 4 root root 4 Jul 28 18:06 .
512 drwxr-xr-x 3 root root 3 Jul 28 17:50 ..
512 drwxrwxrwx 2 root root 2 Jul 28 18:04 home_movies
512 drwxr-xr-x 2 root root 2 Jul 28 18:06 photos

/mnt/vault/home_movies:
total 1.0K
512 drwxrwxrwx 2 root root 2 Jul 28 18:04 .
512 drwxr-xr-x 4 root root 4 Jul 28 18:06 ..

/mnt/vault/photos:
total 1.0K
512 drwxr-xr-x 2 root root 2 Jul 28 18:06 .
512 drwxr-xr-x 4 root root 4 Jul 28 18:06 ..
root@truenas[/mnt/vault]#

Then I started copying data via NFS and I ended up with something quite strange:

Code:

root@truenas[~]# zfs list -r vault
NAME                                                     USED  AVAIL     REFER  MOUNTPOINT
vault                                                   4.24T  11.5T     4.24T  /mnt/vault
[...]
vault/home_movies                                        140K  11.5T      140K  /mnt/vault/home_movies
vault/photos                                             140K  11.5T      140K  /mnt/vault/photos

It looks like the data is being poured into the main mountpoint and not into the child datasets.

After some investigation I think it may be a bug in TrueNAS SCALE thou. I was changing dataset options multiple times and I believe TNS didn't do a proper NFS restart after remounting the ZFS dataset. This essentially caused the NFS to create "home_movies" and "photos" *directories* in the main /mnt/vault hiding the real mounts:

Code:

root@truenas[~]# mkdir /tmp/mount
root@truenas[~]# mount --bind /mnt/vault /tmp/mount
root@truenas[~]# ls -l /tmp/mount/home_movies | wc -l
76
root@truenas[~]# ls -l /mnt/vault/home_movies | wc -l
1
root@truenas[~]# du -hs /tmp/mount/*
1.0T    /tmp/mount/home_movies
3.3T    /tmp/mount/photos
root@truenas[~]# du -h /mnt/vault/
512    /mnt/vault/home_movies
512    /mnt/vault/photos
1.5K    /mnt/vault/

This seems to confirm my thesis but I'm not sure how I really managed to do that and if this is my fault or not.

 

[anodos]

The NFS server won't by default traverse dataset mountpoints (because they are distinct filesystems). Were you exporting /mnt/vault or /mnt/vault/home_movies?

 

[kiler129]

Were you exporting /mnt/vault or /mnt/vault/home_movies?

The whole /mint/vault to transfer some real-world data for testing.

The NFS server won't by default traverse dataset mountpoints (because they are distinct filesystems).

Hm, interesting observation. I need to play with that then. I was under impression that if the share contained both datasets mount points it will land in the correct dataset or throw an error.

Either way this looks like a bug/oversight as without *nix knowledge a normal user wouldn't discover how the data is and isn't there ;)

 

[Patrick M. Hausen]

NFS is per filesystem/dataset and never traverses mount points. You need to share each one individually.