How many nodes can be in one cluster?

[e100]

The wiki says "A Proxmox VE Cluster consists of several nodes (up to 16 physical nodes, probably more)."
http://pve.proxmox.com/wiki/Proxmox_VE_2.0_Cluster

I currently have 15 nodes in one of our clusters and plan to add two more for a total of 17.
In the future I could see us reaching 20 servers in this cluster.

Is there a limit to the number of nodes, if so, what is the limit?
Is there anything that can be adjusted to increase the limit?

 

[dietmar]

Is there a limit to the number of nodes, if so, what is the limit?
Is there anything that can be adjusted to increase the limit?

The used corosync settings are optimized for less than 16 nodes. If you run more, you may need to
change totem protocol timeouts (man cororync.conf).

 

[e100]

The used corosync settings are optimized for less than 16 nodes. If you run more, you may need to
change totem protocol timeouts (man cororync.conf).

I am not finding much information about this but here is what I found so far.
The man page does refer to some values that might need changed for > 32 and > 64 nodes.

join, token and consensus are three timeouts that might need changed based on what I have read on various mailing lists.

token is 1000ms by default
consensus is 1200ms by default
join is 50ms by default

This mail thread seems to have some good info on large corosync clusters:
http://www.mail-archive.com/openais@lists.linux-foundation.org/msg04232.html

One person said that token=1s and consensus=5s worked for his 48 node cluster.
Based on that I assume that if I slightly increased consensus my 17 node cluster would be fine, might even be ok without making any changes.

 

[dietmar]

One person said that token=1s and consensus=5s worked for his 48 node cluster.
Based on that I assume that if I slightly increased consensus my 17 node cluster would be fine, might even be ok without making any changes.

Yes, I also think it will work.