I’ve gotten a few questions from customers about VMware going to ESXi as their strategic direction and what this meant to VMware backup in the future.  I promised that I’d post something about this since there seems to be a lot of confusion with regard to VMware’s roadmap and strategic direction with respect to ESX and ESXi.

The core message that VMware has made concerning ESX versus ESXi may be found here (along with a succinct comparison of the two.)  A summary taken directly from this post is

  1. The functionality and performance of VMware ESX and ESXi are the same; the difference between the two hypervisors resides in their packaging architecture and operational management. VMware ESXi is the latest hypervisor architecture from VMware. It has an ultra thin footprint with no reliance on a general-purpose OS, setting a new bar for security and reliability (learn more).
  2. In the future, ESXi’s superior architecture will be the exclusive focus of VMware’s development efforts.
  3. New and existing customers are highly encouraged to deploy ESXi. Many Fortune 100 companies have already standardized on the ESXi platform.

Wikipedia has a section concerning this (although they note that a citation is needed) which reads

The Service Console is a vestigial general purpose operating system most significantly used as the bootstrap for the VMware kernel, vmkernel, and secondarily used as a management interface. Both of these Console Operating System functions are being deprecated as VMware migrates to exclusively the ’embedded’ ESX model, current version being ESXi.

So what does this mean for people who need to choose between ESX and ESXi?  It means you need to choose ESXi unless there’s a reason not to.  What would be a reason not to?  Some feature needed that is not in ESXi.  A good guide to a comparison of ESX versus ESXi in VMware 3.5 and for ESX versus ESXi in VMware 4 was just updated a few months ago by VMware.

There’s also a pretty good very recent article on ESX versus ESXi here in which some of the issues of migration to ESXi are raised from a practical perspective.

So, since this is a backup blog, what are the consequences of this?  Actually, very little.  Ensuring that your vendor has support for the vStorage API set, even if you’re using embedded virtual machine backup or using VCB, will allow you to move into the future knowing that you’ll be able to backup  not just VMware 3.5 and vSphere 4 versions but will also allow you to know that in the future you’ll be covered as well.


  1. I used to work at VMware as a tech support engineer, and all of us thought that the ESXi machines were junk because we were always working “under the hood” to diagnose and fix problems. It's when things are broken you have to get under the hood that the differences between the two become significant. The esxcfg tool set is completely missing from ESXi as is vmkfstools. ESXi doesn't log as much information as ESX, and you have to manually configure it to log to a syslog server as opposed to local disk, which only works when things are working properly. That doesn't help you much when things are busted… A good systems technician is one who can investigate and diagnose problems that have been hitherto unknown, and ESX gives you a fighting chance whereas ESXi throws you an anchor when your canoe springs a leak.

    Have you ever tried to fix a broken snapshot CID chain? Have you ever tried to manually clone a VM? There have been times when customers called me with Production VM's being down due to snapshots being in an inconsistent state and the only way to bring 'em back was to get under the hood. You can't do that with ESXi.

    Anyone who tells you that ESXi is just as good or better than ESX is someone who wouldn't have a clue without a GUI in front of 'em.

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