[SOLVED] Quorum and cluster question

[SirSeyop]

Hello,
I'm not experienced in clusterimg, I just use it.
The situation is the following:
7 blades in IBM BC (Uplink 1 Gig connection to switch)
1 standard rackable server (4x1 Gig uplink connection to switch (Lacp))
3 DELL "brutal" servers native Proxmox (10 Gig uplink on each)
1 DELL "proxmox nested in Vmware" (10 Gig uplink on Vmware)
All nodes running with Proxmox 8.1.10.
All are in one cluster. I would like to retiring the IBM BC. So I would like to switch off them step by step (I wouldn't like to remove from cluster until all VMs not migrate to DELLs and I not tested them for a week or two on the new environment).

No HA group, no HA resources is defined.

I powered off two blades already and the pvecm status shows the attached pic.
Can anybody explain the "Votequorum information" section?
When will the cluster break apart (not quorumable)?
The blades are nodeid 2,3,4,5,6 (nodeid 1,8 powered off not removed from cluster).

Thanks if anybody explain the truth.

 

[gurubert]

You need at least 7 online nodes in the cluster to form a quorum.
If there are less than 7 nodes that see each other the cluster will stop working.
Why? Because the cluster logic has to assume that the other nodes are connected somewhere else (network split brain) and can form a majority there. This would lead to data conflicts in the cluster database.

 

[SirSeyop]

You need at least 7 online nodes in the cluster to form a quorum.
If there are less than 7 nodes that see each other the cluster will stop working.
Why? Because the cluster logic has to assume that the other nodes are connected somewhere else (network split brain) and can form a majority there. This would lead to data conflicts in the cluster database.

OK.

If I understand well, in 12 nodes cluster have to vote 50% of nodes + 1.
So, the votes have to be larger or equal of 7. If I add for 1 extra vote for node 9,11,12 then the cluster still alive.
node 9 has 2 votes
node 11 has 2 votes
node 12 has 2 votes
node 7 has 1 votes
node 10 has 1 votes
Those nodes are still alive after blades goes offline.
So, there is a total votes 8.
Is my thinking right?

TY

 

[SirSeyop]

So,
My opinion was success, after edit the votes of nodes if I stopped the blades the quorum was stable.
Thank You!