Yes you are right, but if there are backups in the background it wont be bad to have a fast drive. Also i dont need that much storage on the main disk, so 128gb is more than enough. And this Modules doesnt cost that much more than a similar 1 or 2 tb drive.
Can you explain in detail what you mean that there could be problems with getting ubuntu up to date by using ZFS?
The Snapshots are very good to handle and to migrate the Server, its indeed a very good idea, thank you.
Can you make a snapshot of the Database or do you need to Dump them? I cant really believe that theres no problem if Nextcloud is writing changes in the DB and theres a automated Snapshot at this moment.
I will also use a USB Drive to Backup the Status of the Main SSD, rsync System directories, the Virtualbox Image + Snapshots and the Content of the Raid.
Is it useful to use a extra Partition in the Raid for the Backups of the Main System and VM?
i would rsync the SSD to both disks (Raid + SSD), it wont contain this much space i think.
I don’t really have claims to backup my statement about ZFS in it’s current version(supported since Ubuntu 16.04). It’s just that it’s still new and unproven on Ubuntu, and I generally stay clear of those relatively new and unproved technologies because of past troubles.
For hypervisor snapshots: you are right about (Linux) database datafile consistency. Although chances are slim that it’s going to be really corrupt after a restore, you could just create a regular database dump to file or stop the Mysql/MariaDB(!!) server just prior to backup, and start it after the snapshot is created(that takes a few seconds normally - of course backup takes longer but that doesn’t matter as the database is in consistent state in the snapshot).
I would not create an extra partition in the RAID for the backups, as I would backup it to external storage directly(USB or NAS).
I Realised Debian with ZFS and Snapshots for the Server, but i got two strange things that i needed to Workaroud, couldnt fix this.
-Couldnt mount zfs as /var , not even with mountpoinht=legacy and fstab…
as a Workaround i created two Datasets on which i set the mountpoint to /var/www and /var/lib/mysql
-Snapshots doenst work as expected.
Snapshots with Webserver and Database running was possible, restoring not. Mysql fails to start (cannot create socket which is in same Directory an only generated if its running).
Snapshots are now implemented like this:
sudo -u www-data php /var/www/nextcloud/occ maintenance:mode --on
sleep 1
service apache2 stop
sleep 1
service mysql stop
sleep 1
zfs snapshot -r Intern@original8
sleep 1
service apache2 start
sleep 1
service mysql start
sleep 1
sudo -u www-data php /var/www/nextcloud/occ maintenance:mode --off
Restoring this was no Problem.
Anyone got the same Problem with this?
Now iam getting used to the Idea to Use FreeNAS with ZFS and implement a jail or Vm with Nextcloud. I think this will be a much better, reliably Setup