It's Just Another Layer » cluster http://itsjustanotherlayer.com Virtualization is a layer in software. What are you abstracting away from? Fri, 30 Jul 2010 16:38:21 +0000 http://wordpress.org/?v=2.9.2 en hourly 1 Cluster size of 8 is the only size to do http://itsjustanotherlayer.com/2009/06/cluster-size-of-8-is-the-only-size-to-do/ http://itsjustanotherlayer.com/2009/06/cluster-size-of-8-is-the-only-size-to-do/#comments Mon, 01 Jun 2009 19:34:58 +0000 iguy http://itsjustanotherlayer.com/?p=158 For a large organization that has more than 8 VMware Hosts (nodes) one should only make 8 node clusters for the time being according to the vSphere 4 Config Max doc.

http://www.vmware.com/pdf/vsphere4/r40/vsp_40_config_max.pdf

If you look on page 7 it says “Configurations exceeding 40 VMs per host are limited to cluster size no greater than 8 nodes“.  

What that means is to be supported you have the following chart:

8 Nodes  x 100 VMs / Node  == 800 VMs per cluster max

9 Nodes x 40 VMs / Node     == 360 VMs per cluster max

20 Nodes x 40 VMs/ Node    == 800 VMs per cluster max

32 Nodes x 40 VMs / Node   == 1,280 VMs per clustre max

Now I might not be too smart here some days though I think the math is pretty obvious.  Either I do 4 clusters of 8 nodes to give me 3,200 VMs on 32 boxes or I stick them all into one nice big cluster and get 1,280 VMs out of those 32 boxes.   Easy math to me.  

The question I have out of this is, why do you document it this way?  That sure is confusing and I could have easily missed that.

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