Zfs disk size question.

[ozgurerdogan]

I have a 4 TB Disk and mounted as zfs. I also created an other one with command:

zfs create D4/BACKUPS -o mountpoint=/D4BACKUP to store disk backups.

But their sizes are different. Please see screen shot. Also their used spaces are also different. Probably because it has zfs snapshot and disk backups. But why total size is different?

 

[Dunuin]

Outputs like zpool list, fdisk -l, zfs list -o space -r, lsblk would be helpful.

 

[ozgurerdogan]

root@backup:~# zpool list
NAME    SIZE  ALLOC   FREE  CKPOINT  EXPANDSZ   FRAG    CAP  DEDUP    HEALTH  ALTROOT
D2D3   7.25T  2.74T  4.51T        -         -    17%    37%  1.00x    ONLINE  -
D4     3.62T   834G  2.81T        -         -    15%    22%  1.00x    ONLINE  -
rpool  3.62T  3.15T   486G        -         -    49%    86%  1.00x    ONLINE  -

Other commands creates a long list. I can still send them.

 

[Dunuin]

D4/BACKUPS ist just a dataset ontop of your D4 pool. And ZFS uses thin provisioning and each dataset is its own file system. So the fuller your D4 pool get, the smaller the dataset could be. So your D4BACKUP storages available capaciy will shrink while other datasets, zvols, or the pools root will grow.

 

[ozgurerdogan]

So there is nothing wrong and I can do here?

 

[Dunuin]

No, thats all fine. If you want full 4TB for your D4/BACKUPS dataset just don't store anything on your D4 storage. But if you want the D4/BACKUPS for backups you shouldn't use D4 for VMs/LXCs so you don't loose your VMs/LXCs at the same time as yor backups if your loose your D4 pool.

 

[ozgurerdogan]

This server is only for backup for both zfs snapshot and normal backups. So I think it is ok.