2 Node HA with external QDevice

[fluppy]

We are currently running a single proxmox server to host our VMs, and I would like to build some redundancy. I was thinking of ordering an identical spec server to basically have a mirror. We also have some old servers laying around we can use for the quorum as I've read that you need 3 servers to achieve HA in Proxmox, however we don't want the VMs to run on this 3rd server as it will be old hardware.

For this 3rd server, do we have to run Proxmox on it? Or can we use it as a QDevice? I'm not sure what this means, would really appreciate an explanation and pointers.

 

[bbgeek17]

In Proxmox cluster a software package called Corosync is used to maintain the cluster membership and decision making. A normal Proxmox node, which is a member of a cluster, runs a full Corosync service.
Qdevice is a light-weight vote caster designed to work within a Corosync cluster. Qdevice service does not need to run on an equally powerful server, or even same OS as the Proxmox. You can run multiple Qdevice services on single server to service multiple PVE clusters. You can run Qdevice service on Raspberry device.

Yes you can run Qdevice on an old server. To do so you need to follow instructions https://pve.proxmox.com/wiki/Cluste...External Vote Support,-This section describes

You can also run normal PVE software on the old server to get 3 members, and restrict HA to only 2 primary servers.

Good luck

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Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox

 

[fluppy]

Oh you can involve Pis? That's great I got a load of them lying around.

Is 2 servers + 1 PI sufficient? Or should we be using 2 Pis?

 

[bbgeek17]

If you have 2 servers and 2 PIs, then you have 4 vote casters which leads to potential 2/2 split which puts you back into same position as having 2 nodes with 1/1 split.
You need an odd number of cluster members for proper operation.

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Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox

 

[fluppy]

Ok I see, I'll probably just do a single Pi then and have an extra one as a cold spare ready to swap in if the Pi itself dies.