PVE and PBS - ZFS needed on both?

[mgaudette112]

Hi,

I am very much of a new Proxmox user, have only configured one as a test. I am looking to use old servers, without HBA cards, so ZFS is, at least for now, not possible. but I am willing to build a proper ZFS PBS server to go along with the PVE(s). (I have some basic ZFS knowledge as I have studied ZFS and hardware requirements for another project) so I understand the need for direct HDD access.

My question is a basic one - Is the ZFS advantage on PBS only relevant if PVE also uses ZFS? I am planning on having PVEs use LVM with qcow2 (to allow for snapshots) - I am not sure what I am losing on the backup side (specifically) by not using ZFS on the PVE hosts.

Or is the PVE host filesystem irrelevant and I am planning the best PBS possible by making sure the PBS is using ZFS, regardless of PVE?

 

[Dunuin]

My question is a basic one - Is the ZFS advantage on PBS only relevant if PVE also uses ZFS?

No. PBS won't make use of ZFS replication.

I am planning on having PVEs use LVM with qcow2 (to allow for snapshots)

LVM-Thin would also allow for snapshots without qcow2 and that additional filesystem.

I am not sure what I am losing on the backup side (specifically) by not using ZFS on the PVE hosts.

Nothing except that you could never really trust your data when not using a filesystem with checksumming like ZFS and ECC RAM on the PVE nodes. Maybe some data of a VM corrupted a year ago and you never noticed it because the VMs wasn't crashing and you don't access that data often. Then your PVE would have backed up that corrupted VM for a year and all those backups only contain that corrupted data.
The verify jobs of PBS won't help as they only check if the chunk files of the backup snapshot didn't change after uploading them to the PBS. If you backup data that already got corrupted on the PVE host, PBS will tell you that your backups are fine, even if the data they contain isn't.
Use ZFS with its data integrity checks on the PVE nodes and its monthly scrub would identify this corruption, fix it with its parity/mirrored data and warn you about it.

 

[mgaudette112]

No. PBS won't make use of ZFS replication.

That is the technical way of wording it - thank you, that was exactly where I was going with my convoluted question.

I guess I am not losing anything but not using ZFS on PVEs PBS-wise . I understand the rest of the disadvantages.

I will have to trust HP RAID cards do the data-integrity checks on the PVEs until I upgrade the servers in a few months, which is my plan if I like Proxmox as much as I think I will - I'm still putting it through its paces.

 

[_gabriel]

pbs include a verify job that read all the data to check integrity.
don't forget to schedule it

 

[mgaudette112]

pbs include a verify job that read all the data to check integrity.
don't forget to schedule it

Thank you, will do.