HA and quorum

[benoitc]

I would like to setup a fault tolerant system with 2 nodes only in an Active-Passive pattern with the passive node getting all the data replicated to it. According the documentation [1] we can add an external node to maintain the quorum. Can it be used in a pseudo HA system with the data on a shared file system? Is 2 PVE nodes enough for such design? What would be the other way to do it?


[1] https://pve.proxmox.com/wiki/Cluster_Manager#_corosync_external_vote_support

 

[dcsapak]

yes this should work, note the special considerations for storage replication with ha: https://pve.proxmox.com/wiki/Storage_Replication#:~:text=High-Availability

 

[benoitc]

yes this should work, note the special considerations for storage replication with ha: https://pve.proxmox.com/wiki/Storage_Replication#:~:text=High-Availability

what if i use a shared storage? Would it also work with only 2 PVE nodes? Or do I need absolutely 3 nodes?

 

[ph0x]

If you're referring to Ceph: third node is a must. If you're referring to NFS/iSCSI from another server then you're good with two.

 

[benoitc]

i was indeed thinking to iscsi. Thanks for the answer!

 

[ph0x]

The storage server can as well act as the quorum device, then.

 

[benoitc]

The storage server can as well act as the quorum device, then.

indeed. Iwonder if it can be don eon a QNAP NAS...

 

[ph0x]

You'll need the corosync qdevice service. Don't know if this exists for QTS natively. You could run it in a container if your NAS supports that.

 

[benoitc]

yes this should work, note the special considerations for storage replication with ha: https://pve.proxmox.com/wiki/Storage_Replication#:~:text=High-Availability

I'm notre sure to understand the doc correctly. Does it means that in case of failure a node will still be restarted automatically in case of failure on the other node ? Or does this require a manual operation?

 

[Astraea]

People have also used a small system such as a 1L PC (or other SBC that is X86) or a Raspberry Pi as a quorum device.