Monday, February 20, 2012

Do you need VMware ESX? (vSphere)

Update:1 – corrected some numbers. Thanks @jasonboche

Let me just say I love VMware, particularly ESX and have worked with it from before GSX was in shorts, back in the workstation days, when only para-virtualisation existed. I have rolled out ESX 2/3/4 farms (no 5 yet)… I have never had a purple screen of death, I have never had to rollback a workload to hardware, I have VMed Exchange 2k/2k3/2k7, DCs 2k-2k8r2, file & print, SQL servers, Citrix servers they all run great on ESX/ESXi.

But do you need it? Or are you after a solution has all the features, are you after the Rolls Royce? What are you really trying to do? Are you exotic or somehow special?

You want ESXi that's fine, go ahead I don't get paid either way, but then nor does anyone so please do.

Lets just think about what server virtualisation does (as of todays date):


ESX/ESXi Hyper-V XENserver

Bare-metal architecture

Yes No, but core Yes
VMotion like Yes Yes Yes

Small footprint

Yes No, but core Yes-ish
Cluster (pool) 32 nodes 16 nodes 16 nodes

CPU virtualisation

Yes Yes Yes
RAM Support Host 2TB 1TB 1TB
RAM support VM 1TB 64GB 128GB
RAM overcommit Yes Yes Yes

NIC teaming

Yes No*/vendors Yes

VM RAM Page sharing

Yes No No


Yes Yes Yes

Capacity prioritisation

Yes Yes-ish Yes-ish

Traffic Shaping

Yes No No

Virtual NIC

Yes Yes Yes

Virtual switches

Yes Yes Yes

VLAN tagging

Yes Yes Yes

Dynamic volume resizing

Yes Yes Yes

Raw device mapping

Yes Yes Yes

LUN management

Yes Yes-via vendors Yes-add on
Guest Windows Yes Yes Yes
Guest Linux Yes Yes-limited Yes-good
Guest Other Great OK Good


None (good!) Yes, LAN/Disk yes-ish

Distributed Power Mgnt

Yes Some Some

Wake-on LAN

Yes No No

There are hundreds more features such as “Boot from SAN” which are specific or particular so I have not listed them above, if YOU need them they are critical but lets just focus back on the 99%

So to look at this list above there are some clear areas where ESXi wins out, specifically on the very large scale, telco scale, intensive power saving, dare I say cloud providers… But if you are one of the people who just need a bunch of VMs per server for general workloads any of the three products above is going to work fine. Scale up the CPU, RAM, Network cards and you can go to higher density?

The limits are disappearing.

So now lets look back at yourself, do you really need ESX? Maybe you could save some money… Look around.

Just before signing off, read this:

This document is the source for the core of this post:
Intel: “xeon_7500_Virtualization_solbrief.pdf”

* Microsoft say dont use teaming, but vendors support it. Buyer beware… Microsoft Support Policy for NIC Teaming with Hyper-V -

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