Tiny/Mini/Micro low-power hardware for PBS at home?

[lmm5247]

I'm running Proxmox at home on a single server and currently have backups setup to dump to a NAS. This obviously takes up a lot of space, since each backup is full-size.

I'd like to setup PBS on a separate piece of hardware. Ideally, it would be a Tiny/Mini/Micro box that is low-power. I only have a handful of VMs, so I can't imagine I'd need much power for backups, right? I'd like to have a small SSD as the boot OS (for PBS) and mount a backup share that PBS dumps backups to.

I'm currently thinking any of these. Thoughts? Networking is all 1Gbps and I only have 8 VMs (home user).

• Dell Optiplex 5060 MMF - Pentium Gold G5500T (2c/4t) - $259
• Dell Optiplex 3050 MMF - Core i3-7100T (2c/4t) - $209
• Dell Optiplex 3070 MMF - Core i3-9100T (4c/4t) - $399

 

[Dunuin]

Keep the storage requirements in mind. PBS needs IOPS performance, so recommended is local SSD storage for your backups. In a homelab with very few backups (couple hundred GBs) a NFS share on a NAS with HDDs might be fine. With more backups you better get a machine that can fit some HDDs + SSDs.

 

[lmm5247]

Keep the storage requirements in mind. PBS needs IOPS performance, so recommended is local SSD storage for your backups. In a homelab with very few backups (couple hundred GBs) a NFS share on a NAS with HDDs might be fine. With more backups you better get a machine that can fit some HDDs + SSDs.

I'm backing up to a NAS with HDDs now, so I figured PBS should be able to do the same. But yes, current backups (the full-size backups) are 220GB total.

 

[mfed]

Pretty sure any one of those servers will work. I had a PBS running on an old Celeron-based mini-PC with 2TB HDD, and it was fine. Just had to disable verification immediately after backups, they would consume too much CPU and made backups to fail..

 

[Dunuin]

I'm backing up to a NAS with HDDs now, so I figured PBS should be able to do the same. But yes, current backups (the full-size backups) are 220GB total.

The difference is that vzdump will backup a 1TB virtual disk as a single 1TB file. PBS will store it as ~500000 small files. And deleted backups won't be deleted until you run a GC task which then needs to read + write all those 500000 files which needs massive IOPS performance HDDs can't handle. And a single corrupted small chunk may break all the backups of a VM, not just a single backup. So you want to run a verify task regularily and this again needs to read and hash all those 500000 files in random order.
HDDs are only useful for sequentially reading/writing big files and this is exactly what vzdump is doing but PBS is doing the opposite (random reads/writes of small files).

So don't expect great performance when putting your datastore on a HDD backed NFS share. And your NAS might not be usable for something else while a verify or GC task is running (which might take hours/days depeding on the size of your backups).

 

[lmm5247]

The difference is that vzdump will backup a 1TB virtual disk as a single 1TB file. PBS will store it as ~500000 small files. And deleted backups won't be deleted until you run a GC task which then needs to read + write all those 500000 files which needs massive IOPS performance HDDs can't handle. And a single corrupted small chunk may break all the backups of a VM, not just a single backup. So you want to run a verify task regularily and this again needs to read and hash all those 500000 files in random order.
HDDs are only useful for sequentially reading/writing big files and this is exactly what vzdump is doing but PBS is doing the opposite (random reads/writes of small files).

So don't expect great performance when putting your datastore on a HDD backed NFS share. And your NAS might not be usable for something else while a verify or GC task is running (which might take hours/days depeding on the size of your backups).

Oof, I didn't know that, thanks for sharing! Sounds like a SSD is a requirement then!

 

[mfed]

BTW, if you want to save the money just add a disk to your existing proxmox server, install pbs there and do the backups to it. For additional protection you can backup the pbs data to your NAS.
From my experience HDD for backups work just fine, but surely if you can afford SSDs that would be better. I do have a noticeable delay and sometimes need to hit 'Reload' a few times before the list of backups populates. I have a 2.5TB worth of backups stored on a slow 2.5inch SMR drive...

 

[Dunuin]

I have a 2.5TB worth of backups stored on a slow 2.5inch SMR drive...

But a GC and full re-verify then probably runs very long. Something like 10 hours?

 

[mfed]

Looked at my logs, the last verification job took 2 hours. Last prune finished in a minute.

Nothing prevents you from trying on your local proxmox server and you should see if it is going to work...

 

[Dunuin]

Last prune finished in a minute.

Prune is always fast but won't delete anything. For that you need to run a GC at least 24 hours + 5 minutes after running the prune.

 

[mfed]

Prune is always fast but won't delete anything. For that you need to run a GC at least 24 hours + 5 minutes after running the prune.

Last GC took an hour and a half.

Anyway, the local HDD seems to be quite fine as a PBS target. I see that you were talking about an NFS storage backed by HDD, and I think I would agree, PBS datastore on NFS mount might not be a good idea, and might not perform well even if backed by SSD (I think the network speed will play a big role)

 

[Dunuin]

Last GC took an hour and a half.

Anyway, the local HDD seems to be quite fine as a PBS target. I see that you were talking about an NFS storage backed by HDD, and I think I would agree, PBS datastore on NFS mount might not be a good idea, and might not perform well even if backed by SSD (I think the network speed will play a big role)

Jup. Here it is more like 4-6 hours for a GC of a 1.15TB datastore on a 4 disk raidz1 using HDDs over NFS with a 10Gbit connection.