Migrate to a new cluster

[LeMishoK]

Thank you all for all the answers. I wanted to go the easy way, but I decided to build the new proxmox server "from scratch" at this time.
Continuing with my noob questions.

I have 4 identical Dell Optiplex 5050 Micro, i5 7th gen, 16Gb RAM, each machine has 2 drives: 180Gb NVME (for the system), 500Gb SSD for storage. One machine out of 4 has 500Gb NVME instead of 180Gb that other 3 machines has.
PCs has 1gb ethernet network card, no WiFi module.
All 4 will be connected to same gigabit switch, switch will be connected to router.
I already have a TrueNAS as a separate old DELL tower. I will be using TrueNAS as an external storage (like for Immich and Shinobi).

Now questions:
1. Each of 4 machines has absolutely identical 500Gb SSD drive, same brand, same model. I would like to set that up so they are mirroring each other like a RAID or whatever, so if 1 (or 2 or 3 of them) out of 4 drives dies I still have at least one drive that still works. Or even make it so I have like 2x1Tb instead of 4x500Gb. Is it even possible? It will be used for VMs and Containers installed. Each of 180 + 180 + 180 + 500 NVMEs will be only used for the proxmox itself.
Being noob in this topic, I am using analogy like installing Windows on 1 drive, and installing all apps and games on the 2nd physical drive.

2. During initial setup of Proxmox on each machine, what filesystem should I choose to set it up the way I described in my 1st question?

Thank you.

 

[alexskysilk]

. Each of 4 machines has absolutely identical 500Gb SSD drive, same brand, same model. I would like to set that up so they are mirroring each other like a RAID or whatever, so if 1 (or 2 or 3 of them) out of 4 drives dies I still have at least one drive that still works.

see https://pve.proxmox.com/wiki/Storage_Replication

Or even make it so I have like 2x1Tb instead of 4x500Gb. Is it even possible?

Possible- yes, but not in the way you're thinking. install all 4 drives in one machine. You're already doing this with your old dell tower. as an aside, concatenating disks (just adding two drives into a single volume) exponentially impacts the odds of loss (2 disks worth for 1 failure.) What you'd want to do is a striped mirror (4 disks, 1TB payload.)

2. During initial setup of Proxmox on each machine, what filesystem should I choose to set it up the way I described in my 1st question?

the only thing you'll be setting up is pve; since you're not intending to use the drive for virtualization payload, just use ext4.

 

[J-Rod]

The 5050 micro only has space for one NVMe and one 2.5" SATA drive.

I would propose setting up the three identical 5050 Micros in their own cluster. When installing PVE on the NVMe drives, you can use ZFS but reduce the size by 16GB during setup to leave space for swap if you need it later (you probably will with only 16GB RAM).

Set up the 500GB SATA SSDs with ZFS and use ZFS storage replication as mentioned. Replicate VMs from host 1 to 2, replicate 2 to 3 and finally 3 to 1. This is the configuration I run and it allows you to migrate all of the VMs from host 1 to 2 without shutting them down in order to perform maintenance. Then migrate them back after updating the host, then rinse and repeat. If a host dies, you have the VM data available on the other host, but do be aware the fastest replication available in PVE is every 1 minute.

I would use the 4th host that is not identical to the others for PBS and a disaster recovery host. Install PVE, then install PBS in a VM and back up your VMs to it. If your cluster goes TU, you can restore some critical VMs to the 4th host while you work on the cluster.

With regard to the migration, I think any of the three options I mentioned previously would work. Up to you to decide which you prefer.