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ESXi is as small as VMware says it is…

definitive answer to the question: if ESXi is so small – how come it needs a 2GB memory stick, and occupies more space than the alleged 30-60MB claimed by VMware?

A couple of days ago I commented on MS's recent spate of articles about the surface footprint of the hypervisor.

My takeaway question was as follows: if ESXi is so small – how come it needs a 2GB memory stick, and occupies more space than the alleged 30-60MB claimed by VMware?

Well, I think Eric Gray over at has made the definitive answer…

It appears much of what is resident on the stick, does not include what is resident in memory. For example the ESXi stick contains a copy of the Vi Client and also the .ISO images used by VMware to install VMware Tools to the guest operating system. Additionally, as ESXi can be “rolled back” after an upgrade/patch – there has to be space on the stick to hold this roll back data.

Of course, that might lead you to say – “ah, you see VMware are telling fibs”… But IF you recall the original argument/case for a small hypervisor – it has to do with its vulnerability/weakness in terms of performance, patching and security. The smaller the hypervisor is, the less vulnerable it is. Unfortunately, this view of the hypervisor is decidedly NOT shared by Microsoft. Microsoft firmly believes the virtualization layer should live inside the operating system. It’s an ideology that many Microsoft bloggers publicly subscribe to and endorse. I don’t.

I subscribe to the VMware ideology – that the hypervisor should be superslim. With APIs like vStorage/vNetwork that allow third parties like EMC, NetApp and Cisco to “hook” into. Without bloating out the hypervisor with 3rd party unchecked code, that;s responsible for so much instability in the Microsoft platform. If you don’t believe in the VMware ideology, what you believe in is the same vulnerabilities and patch management that bedevils a vanilla operating system like Windows, Linux, Solaris and Netware…


 I’ve got something add to this. And it’s not going to be pretty. IF Microsoft will persist on patiently avoiding the technical acts on their blogs in an effort to make their product look as good as/better than VMware. I think we can discount this kind claptrap about MS not being free to present their products at next weeks VMworld, as unreliable information… 

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