I've been running a home server with Arch Linux (i7-3770, 16 GB RAM) for a few years now. It's a mix of Docker containers and some services directly on the host system. I'm trying to move everything to containers though.
For storage, I'm currently using a 256 GB SSD for the host system and three 6 TB HDDs in a RAID 5 for data storage. Backups are currently stored on the same hardware (not the best idea, I know) with Borg Backup.
I wanted to upgrade and rebuild my home server setup as I have a PC I don't use anymore (i7-8700K, 32 GB RAM), two 18 TB HDDs, a 256 GB PCIe m.2 SSD and a 1 TB PCIe m.2 SSD.
So my available hardware is this:
PC 1 - i7-3770, 16 GB RAM, 256 GB SATA SSD, 3x 6 TB HDD
Initially, I wanted to just move everything to PC 2 and be done with it but I've stumbled upon Proxmox and wanted to check if it makes sense to build a nice setup with this. At least some of the Docker containers could be converted to LXC or VMs. The rest could stay as Docker containers in a VM I guess.
I could do something like this:
PC 1 as a Proxmox Backup Server host
PC 2 as a Proxmox VE host
A lot of data on the current 12 TB RAID 5 doesn't need to be backed up so 12 TB just for backup storage should be enough.
I'm not sure if that's the best/most efficient way to use this mix of hardware, maybe someone has a similar setup or other advice :) I'm also trying to save as much energy as possible even though that might be hard with 2 physical servers. (Does Proxmox BS turn off HDDs when they're not in use?)
I'm not super fixed on Proxmox although it does look like it's easy to manage without a lot of maintenance involved.
I would move to the new PC2 with the intent of decommissioning PC1 later, since you want to save power running 2 systems doesn't make too much sense. And PC2 has tons of resources so you shouldn't have any limitations.
If you wanted to keep the 3x 6TB drives you could move them to PC2 as well.
Proxmox is great, very easy to manage and minimal maintenance. It has ZFS support so you could do a mirror with the 2x 18TB drives if you wanted to.
How would I handle backups though? I have some data I should definitely back up in some way, e.g. Nextcloud or paperless-ngx. A mirror is good but doesn't replace a backup :D
That's why I brought in Proxmox Backup Server, not sure if that's overkill though or if I can backup using Proxmox VE itself. I've also read about people running Proxmox Backup Server as a VM inside Proxmox. That way I only have one physical machine but I'm not sure how complicated it would be to access the backups if the Proxmox VE host itself goes down.
In my case what I do is backup the Proxmox Backup Server VM to my desktop PC over the network, so if my Proxmox host fails I can:
Reinstall Proxmox on the host or some other host
Restore the Proxmox Backup Server VM that's saved on my desktop PC
Once that's running, I have access to all the other backups and can restore the rest of the VMs and Containers
Obviously that's assuming the drives haven't failed for some reason, if that's the case I also backup important stuff with Restic inside each VM and Container, and that gets stored on Wasabi S3 or Backblaze B2. Those backups are if everything else fails, a lightning strike takes it all out, or there's a fire or something. They would require rebuilding from scratch, but the important data is at least saved.
PBS is a good backup solution, and it will also replicate to an external harddrive if you want an offsite. The backups are navigable/downloadable in the interface and with the CLI client, you could restore full trees back to a system or VM, besides being able to restore the whole image into a new VM. It also dedups quite heavily so you can keep months of images on little disk space.
Personally, I would leave PBS separate on a weak computer, it doesn't take much of a system to run it, for the reason you state. You can also backup the PVE host to that computer using rsync on the important bits like the /etc/pve folder as per the forum suggestions.
If you have other questions you can't get answered here, consider signing in to https://discourse.practicalzfs.com where there a number of Reddit refugees to answer questions. There's also some Proxmox forums on Lemmy here but none are very active yet.