[SOLVED] mysterious ZFS-Pool usage - who can help troubleshooting?

[nigi]

Hi, my disk space on a ZFS pool is almost used but I don't know why.
There are 3.22 T used, but I can't see why.

~# zfs list -t filesystem -o space
NAME                             AVAIL   USED  USEDSNAP  USEDDS  USEDREFRESERV  USEDCHILD
rpool                             752G  4.58T        0B    104K             0B      4.58T
rpool/ROOT                        752G  3.22T        0B     96K             0B      3.22T
rpool/ROOT/pve-1                  752G  3.22T        0B   3.22T             0B         0B
rpool/backup                      487G  12.8G        0B   12.8G             0B         0B
rpool/data                        752G    96K        0B     96K             0B         0B
rpool/vm_pool                     752G  1.33T        0B    128K             0B      1.33T
rpool/vm_pool/subvol-100-disk-0  15.5G  4.54G        0B   4.54G             0B         0B
[...]

I agree with backup, data and vm_pool. But NOT with /rpool/ROOT/pve-1

~# du -sh /rpool/ROOT/pve-1/
512    /rpool/ROOT/pve-1/

Where does this 3.22 T used Space come from? I can't find any files

 

[Moayad]

Hi,

Have you check the output of `zfs get all` command? this will print more information.

 

[LnxBil]

~# du -sh /rpool/ROOT/pve-1/ 512 /rpool/ROOT/pve-1/

That does not exist, try /*

 

[Dunuin]

Your root filesystem uses 3.22TB. Usually thats the case when you manually mount a storage (internal or external Disk, SMB/NFS share) using fstab/systemd and you forget to set the "is_mountpoint" flag for your directory storage. When then the mounting of that share/disk fails you will write your data to the unmounted mountpoint so data will end up on the root filesystem and not on the disk/share it should have been stored on.

You should also check with zfs list -o space if discard isn't working (=high refereservation) of if snapshots preventing ZFS from freeing up space.

 

[nigi]

Hi, of course, I've inspected my mounted directories, first. But obviously very negligent
Thanks for your tip! I've found the missing mount only in the third pass.

But how can I flag a directory as a mountpoint? I didn't know this flag.

Thx
nigi

 

[Dunuin]

Hi, of course, I've inspected my mounted directories, first. But obviously very negligent
Thanks for your tip! I've found the missing mount only in the third pass.

But how can I flag a directory as a mountpoint? I didn't know this flag.

Thx
nigi

That can only be set using the CLI: pvesm set StorageNameOfYourDirectroyStorage --is_mountpoint yes

See: https://pve.proxmox.com/pve-docs/pvesm.1.html

 

[nigi]

OK,
I thought it was an Linux feature. I hadn't thought of PVE. Thanks, I've learned something again!