You have a 32 GB server as your virtualization host You have

You have a 32 GB server as your virtualization host. You have 32 application servers (each has 4 GB of memory) to virtualize on this host server. Assume all servers are running Windows server 2008. Using the basic configuration, how many VMs can be hosted on the 32 GB server? Show your Calculations

Solution

The common rule of thumb is 4-6 vCPU per each pCPU, so you should expect 32-48 VMs.  

However, memory could very well be a limiting factor in how many VMs you can have running. Luckily VBox now has some memory over-commitment features like Ballooning to help with these types of things. Conservatively figure a 15% overhead for the system, that leaves 27GB useable, then figure about 30% overcommit (again being conservative) which brings you to 35GB so you can fit about 35 VMs.

Personally, I\'d start off at 32, that should be no problem, then add and monitor things like memory utilization/swap (avoid swap at all costs) as well as things like CPU Ready (not sure what VBox calls this, should be same)....high CPU ready means that you\'re over taxing the physical cores.