R640 for PBS

[Antoine-UY]

Hello everyone!

I am starting my little proxmox adventure, and quickly came to the realization that a single server running PVE (just bought the server, but did not install it yet) was really a call for a second server to host PBS. At this point in time, I have a functional R640 (48c/96t @ 2.7GHz/3.7Ghz, with 768GB of RAM and 15TB of NVMe/SATA/SAS disks). And a bunch of extra R640 spare parts (a motherboard, more NVMe cables, another BOSS-S1 card, an extra Tesla T4, extra PSUs, etc).

Therefore my questions are the following:
1°) In your view, for a company running heavy virtualization on PVE, is PBS really a "must", or could a more affordable random NAS give us what we're after? Or cheap storage expanders, such as the SC-420? My question really boils down to: what would you gain, having an independent server running PBS, that you wouldn't get from a single PVE server with a lot of extra storage to run backups from inside PVE/a bunch of NAS on the side?
2°) If you could have 2 servers (only 2) and enjoyed a shitload of 8-bay Synos, would you rather use your 2 DELL R640 as 2 PVE nodes, or one as a node and one as PBS for your single PVE node?
3°) Is the DELL R640 suitable for PBS in your view? Is it overkill in computation possibilities and too low on storage possibilities (inferior to an R740), for instance?

The underlying motiv being: would you invest extra cash to build a second R640 using your extra spare parts, for the sole benefits of having a PBS server? Or can most of its benefits be achieved for much less money, and the potential second server be put to better use (another PVE node, or local LLM training)?

 

[MarkusKo]

Hi Antonine-UY

If you have enough NAS storage (NFS) you could use PVE integrated vzdump backups instead of PBS.
Downside is you can't encrypt backups and syncing them offsite (3-2-1 backup rule) needs significantly more bandwith / time - vzdumps are full backups after all.

PBS solves the offsite syncing and encryption issues. If you pull backups from PBS onsite to an offsite PBS you have a better ransomware protection.

Another option would be to virtualize PBS on one of your NAS devices if supported.

You could virtualize PBS on one of your PVE nodes, mount your NAS NFS share inside PBS and backup to that. PBS itself could be backed up via vzdump.
But this is not officially supported, in case something goes wrong you are on your own.

Just make sure PBS storage is fast or at least has some sort of SSD cache for metadata, otherwise backup verification could take too long or even time out (depends on your use case / amount of backups / size ...).

If this is for a company i would prefer to have a second PVE host in case something goes wrong with your first PVE host but that depends on how important your workload is ...

 

[Antoine-UY]

THank you very much for the detailed response. So if I'm following your drift, the main line of argument which could be made for PBS can be opposed to both NAS and inside-PVE-backups. And the crux of it the possibility of incremental backups, which can only be achieved in this fashion. Correct?

 

[MarkusKo]

Yes, from PVE perspective PBS is just a backup data store, PVE backups are the same (like full vzdumps) but PBS deduplicates the backup, stores duplicate chunks only once. So the space requirements for backups on PBS are (in most cases) way lower. And PBS can push or pull backups to another PBS in an incremental way (only new chunks are transmitted).