Extend ZFS zpool of Linux Ubuntu NextCloud VM

If you are running a virtual machine with NextCloud v16 on linux ubuntu and you want to extend /mnt/ncdata, then:

1. Make sure your backup is fine, think about creating a vm snapshot
2. Extend second virtual harddrive disk in VMWare virtual machine settings (e.g. from 40Gb to 170Gb)
3. Login using SSH/VMWare-Console, change to root user using sudo su or sudo -i
4. Check the zpool size using zpool list
5. Check the /mnt/ncdata size using df -h
6. Read the new partition size using parted -l with the answer "fix" for the adjustment
7. You can delete the buffer partition 9 using parted /dev/sdb rm 9
8. Extend the first partition using to 100% of the available size parted /dev/sdb resizepart 1 100%
9. Using zpool online -e ncdata /dev/sdb you can adjust the partition to the correct size
10. Check the new zpool size using zpool list
11. Check the new /mnt/ncdata size using df -h

Example with nextcloud 16 on Ubuntu 18.04:

root@nextcloud:/mnt# zpool list
NAME     SIZE  ALLOC   FREE  EXPANDSZ   FRAG    CAP  DEDUP  HEALTH  ALTROOT
ncdata  39.8G  15.2M  39.7G         -     0%     0%  1.00x  ONLINE  - 
root@nextcloud:/mnt#
root@nextcloud:/mnt#
root@nextcloud:/mnt# df -Th
Filesystem                     Type      Size  Used Avail Use% Mounted on
[...]
ncdata                         zfs        39G  896K   39G   1% /mnt/ncdata
[...]
root@nextcloud:/mnt#
root@nextcloud:/mnt# parted -l
[...]
Model: VMware Virtual disk (scsi)
Disk /dev/sdb: 183GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system  Name                  Flags
 1      1049kB  42.9GB  42.9GB  zfs          zfs-28cd7
 9      42.9GB  42.9GB  8389kB[...]
root@nextcloud:/mnt#
root@nextcloud:/mnt#
root@nextcloud:/mnt# parted /dev/sdb rm 9
Information: You may need to update /etc/fstab.
root@nextcloud:/mnt#
root@nextcloud:/mnt# parted /dev/sdb resizepart 1 100%
Information: You may need to update /etc/fstab.
root@nextcloud:/mnt#
root@nextcloud:/mnt# zpool online -e ncdata /dev/sdb
root@nextcloud:/mnt#
root@nextcloud:/mnt# zpool list
NAME     SIZE  ALLOC   FREE  EXPANDSZ   FRAG    CAP  DEDUP  HEALTH  ALTROOT
ncdata   170G  2.51M   170G         -     0%     0%  1.00x  ONLINE  -
root@nextcloud:/mnt#
root@nextcloud:/mnt# df -h
Filesystem                      Size  Used Avail Use% Mounted on[...]
ncdata                          165G  896K  165G   1% /mnt/ncdata[...]
root@nextcloud:/mnt#



Update 25.12.2020: If you are running Ubuntu 20/Nextcloud VM 20, then follow the instrutions here starting point 7: https://how2itsec.blogspot.com/2020/12/increase-disk-and-zfs-of-nextcloud-vm.html