@S-Pam
Of course that's true.

My car has airbags and is well insured, but I would not voluntarily drive into a wall just to see if it worked.

Hello Olivier,

thanks for the quick response.

Have you seen https://www.youtube.com/watch?v=FfUqIwT8KzI ?

I did not know the video yet, but now I watched it. Thank you.

1. Can you switch to NFS in your FreeNAS? You'll reduce a LOT your required space to make backup/snapshots

We make some tests about 3 years ago. At this time NFS was slower than iSCSI. Overall, we felt better with iSCSI. Are there any other experiences in this regard?

3. Only the first snap will require doubling space, not extra snaps.

Also on thick provisioning?

5. Linux VM: they are aware of a snapshot because of the disk driver they have by default. No problem at all without VSS, it's somehow "bundled".

Did I understand you right, that I could backup a linux VM with mysql database every time without any risk of losing data?

Backup Flow:

• Backup start
• XO takes Snapshot1
• XO exports Snapshot1 to another System
• IF Full-Backup: XO deletes Snapshot1
• IF Delta OR Contiuous Backup: XO archives the snapshot until the next backup run
• Next Delta Backup Start:
• XO takes Snapshot2
• XO "exports" the Delta between Snapshot1 and Snapshot2 to another System
• XO deletes Snapshot1 and keeps Snapshot2 for the next delta backup run
• and so on

So while the backup runs I need space for 1 snapshot when I do a full backup, and 2 snapshots if I do a delta backup.

Is this right?

Thank you very much

Buschi

Hallo,

I have a question about the space I need for backup VM´s to an external storage.

Situation:
We want to setup a new server system using XCP-NG and XO. The SR should be on a freenas ZFS machine connected over iSCSI. So thin provisioning is sadly not possible.

The storage should contains two DB systems (Windows Server 2016 or 2019 with SQL Server Express, Ubuntu 18.04 with mysql). To get a good performance we want to use SSDs in the freenas system.

The Backup Storage should be a freenas system too, but with some large HDDs.

At this moment the space used by both VMs is approximately 430GB (Windows 400GB Linux 30GB). We believe that 700GB space should be enough for the next years (Windows 600GB Linux 100GB).

Because good SSDs are not realy cheap, we don´t want to waste space.

Questions:
Could you please tell me, how many snapshots are required on the SSD SR to make external backups using the different backup methods of XO?
Full Backups
Rolling Snapshots
Delta Backup
Disaster Recovery
Metadata Backups
Continuous Replication

If I need more than one snapshot e.g. for Delta Backups, does the second snapshot also need the full space of the VM?

By the way:
Do you know if Quiesced Snaphots are supported from SQL Server Express?
As far as I read they should, but it was not a reliable source.
I think the ubuntu mysql VM sould not support them - right?

Thanks in advance

Buschi