Title: Unset ZFS legacy mountpoints
Date: 2022-12-12 23:38
Summary: Unset ZFS legacy mountpoints on an OVH baremetal server installed with Proxmox and ZFS
Category: Bloc-notes
Tags: zfs, proxmox, ovh, admin, shell, cli, storage, backup
Status: Published
Translation: true
Lang: en
Slug: unset-zfs-legacy-mountpoint-proxmox-ovh-installation

[Proxmox][pve] with a [ZFS][openzfs] root file system on an [OVHcloud baremetal server][ovh-sd] use _Legacy mountpoints_ (managed via `/etc/fstab`). This is a valid setup but avoid using properties inheritance between datasets. Let’s get gives back to ZFS the mountpoint management with a few configuration.

_initial situation on proxmox after installation_:

```bash
root@server:~# zfs list
NAME      USED  AVAIL     REFER  MOUNTPOINT
zp0      3.29G  1.75T       96K  none
zp0/zd0  91.8M   932M     91.8M  legacy
zp0/zd1  3.20G  1.75T     3.20G  legacy
zp0/zd2   104K  1024M      104K  legacy

root@server:~# grep zp0 /etc/fstab
zp0/zd1	/			zfs	defaults										0	1
zp0/zd0	/boot		zfs	defaults,x-systemd.requires=zfs-import.target	0	0
zp0/zd2	/var/lib/vz	zfs	defaults,x-systemd.requires=zfs-import.target	0	0
```
_reboot to customer rescue to set mountpoints_…

```bash
root@rescue-customer-eu (nsxxxxx.ip-x-x-x.eu) ~ # modprobe zfs
root@rescue-customer-eu (nsxxxxx.ip-x-x-x.eu) ~ # zpool import -f -N -R /mnt zp0
root@rescue-customer-eu (nsxxxxx.ip-x-x-x.eu) ~ # zfs set mountpoint=/ zp0/zd1
root@rescue-customer-eu (nsxxxxx.ip-x-x-x.eu) ~ # zfs set mountpoint=/boot zp0/zd0
root@rescue-customer-eu (nsxxxxx.ip-x-x-x.eu) ~ # zfs set mountpoint=/var/lib/vz zp0/zd2
root@rescue-customer-eu (nsxxxxx.ip-x-x-x.eu) ~ # zfs get -r mounted zp0
NAME     PROPERTY  VALUE    SOURCE
zp0      mounted   no       -
zp0/zd0  mounted   yes      -
zp0/zd1  mounted   yes      -
zp0/zd2  mounted   yes      -

root@rescue-customer-eu (nsxxxxx.ip-x-x-x.eu) ~ # grep zp0 /mnt/etc/fstab
zp0/zd1	/			zfs	defaults										0	1
zp0/zd0	/boot		zfs	defaults,x-systemd.requires=zfs-import.target	0	0
zp0/zd2	/var/lib/vz	zfs	defaults,x-systemd.requires=zfs-import.target	0	0

root@rescue-customer-eu (nsxxxxx.ip-x-x-x.eu) ~ # sed -i '/^zp0/d' /mnt/etc/fstab
root@rescue-customer-eu (nsxxxxx.ip-x-x-x.eu) ~ # grep zp0 /mnt/etc/fstab
root@rescue-customer-eu (nsxxxxx.ip-x-x-x.eu) ~ # zpool export -a
```
_reboot to proxmox, et voilà!_

```bash
root@server:~# zfs list -r
NAME      USED  AVAIL     REFER  MOUNTPOINT
zp0      3.29G  1.75T       96K  none
zp0/zd0  91.8M   932M     91.8M  /boot
zp0/zd1  3.20G  1.75T     3.20G  /
zp0/zd2   104K  1024M      104K  /var/lib/vz
```

_References_:

- [FreeBSD Manual Pages - `ZFS(8)`](https://www.freebsd.org/cgi/man.cgi?query=zfs&apropos=0&sektion=8&manpath=FreeBSD+14.0-CURRENT&arch=default&format=html)
- [Oracle Solaris ZFS Administration Guide - Legacy Mount Points](https://docs.oracle.com/cd/E19253-01/819-5461/gbaln/index.html)
- Thank you _Louis_ 🤝

[openzfs]: https://openzfs.org
[OVHcloud baremetal OS]: https://www.ovhcloud.com/en-ie/bare-metal/os/
[ovh-sd]: https://www.ovhcloud.com/en-ie/bare-metal/
[pve]: https://proxmox.com/en/