What's in ESXi 5.5 for free license and white box users?

With the upcoming release of VMware vSphere 5.5 the free version of ESXi (called vSphere Hypervisor) will also be updated. A lot of users deploy this version at home or in small businesses to learn about virtualization or run non-critical workloads on it - even on hardware that is not officially supported by VMware. What will (not) change for them?


Certainly the most pleasant news is the announcement that the host RAM limit of the free ESXi will be dropped. With the versions 5.0 and 5.1 you can not use more than 32 GB, and what's even worse: ESXi would refuse to boot if your host had more than that. It's a fortune for all free license users that this limitation will be lifted, because RAM is usually the first bottleneck that you run into when deploying server virtualization.

With ESXi 5.5 there are great advancements in scalability: The supported number of physical CPUs per host (new: 320), maximum host memory (4 TB) and the number of NUMA nodes (16) and virtual CPUs per host (4.096) have all doubled compared to version 5.1. But the most important limit that was dramatically increased is the maximum size of a virtual disk (VMDK file). The old limit of 2 TB appeared hopelessly outdated, even for home users, because affordable hard disks with 3 or 4 TB are widely available now. The new maximum size is 62 TB.

New features

The improved GPU virtualization capabilities (now supporting more hardware adapters and a software mode) might also be something to play around with in the home lab. But while looking at the official documents you will notice that they are only configurable using the Web Client (or VMware View). The Web Client is only available with vCenter that in turn does not support the freely licensed ESXi version. There will probably also be a way to activate these features by manually editing a VM's configuration file, but VMware's general strategy to build all new functionality only into the Web Client and not into the legacy vSphere client raises some questions: How will users of standalone hosts (that have only the legacy client available) be able to fully benefit from new features? Will VMware make the Web Client available independently from vCenter? Will they still maintain the legacy client and include new features in it - at least those that are usable with standalone hosts? Or will you be thrown back to using command line scripting or manually editing configuration files, e.g. for enabling GPU virtualization or expanding a virtual disk to more than 2 TB?

It looks like there was no clear answer to this during VMworld, only the statement that this needs to be worked on. I am very curious how they will address that in the GA release.

Driver compatibility

Regarding hardware drivers there is bad news and good news for white box users: With ESXi 5.0 (and 5.1) VMware included drivers for consumer grade network adapters, specifically for Realtek (net-r8168 and net-r8169) and Marvell chip based NICs (net-sky2). The bad news now is that these drivers are not included in the current ESXi 5.5 beta builds. Hopefully this will change until the GA build will be released.

The good news is that with ESXi 5.5 you will be able to still use drivers that were compiled for ESXi 5.0 or 5.1. That means you can not only continue using the built-in Realtek and Marvell drivers of ESXi 5.0/1, but all other officially unsupported ESXi 5 drivers that were developed by the community will most likely also work with ESXi 5.5. At least I was able to update an ESXi 5.1 host with a Realtek adapter to a beta build of ESXi 5.5 while keeping the Realtek driver, and it still worked fine after the upgrade.

I could also verify that the tools that I built to support developers and users of community supported ESXi 5 drivers will also work with ESXi 5.5:
  • ESXi-Customizer for injecting drivers into an installation ISO will work without changes.
  • The driver and software packages that you create with the ESXi5 Community Packaging Tools can also be installed on ESXi 5.5 systems. In their metadata they are flagged to be compatible with ESXi 5.*.
I'm currently working on a new version of the Packaging Tools that will enable you to specify ESXi version compatibility in more detail and have some other enhancements. Stay tuned!

This post first appeared on the VMware Front Experience Blog and was written by Andreas Peetz. Follow him on Twitter to keep up to date with what he posts.


  1. Thanks for the great resource you've made available here Andreas. I'm just beginning to get my feet wet with VMWare ESXi and related products and the first obstacle I'm attempting to overcome is with "No Network Adapters" detected upon installation. So, I'm turning to your excellent application - ESXi-Customizer.
    I'm planning on donating to your project after I've shown myself that I can get all of this set up and begin learning it.

  2. well, ESXi 5.5 just "jumped the shark" for this small-business consultant.
    A new install on a well-tried platform from ASUS went well enough -- needed to buy an intel NIC to install (oh well, still way cheaper than buying an intel board).

    The big issue is the trap that has been set for the likes of us. Not that it wasn't clearly marked with warnings in the vsphere client and documentation.

    First let me note that there is no way my clients will pay the fees for even the least-expensive vmware licensing. But a large number of them have been using vmware products to virtualize their servers since Server 1.0.10, WS 5 (and migrating to esxi shortly after that)

    So, as part of finding my way around, I upgraded my test vm's hardware to version 10, and now the vm is unmanageable. (edit settings in the vsphere client 5.5 tells me that I can't use the vsphere client (I was clearly warned about this) - "use the vsphere web client to edit the settings of this virtual machine")

    but - and it's a big one - there *IS NO VSPHERE WEB CLIENT FOR THE ESXI 5.5 hypervisor*.

    So don't EVER upgrade your hardware using the vsphere client. If you do, be sure to heed the warnings about backing up the VM before proceeding.

    In short, this upgrade to esxi makes me VERY VERY nervous about continuing with vmware as a virtualization platform for my small-business clients. It would be so easy to get caught in a situation where the only way out is to spend an unknown amount of money, and and time, dealing with vmware licensing.

    1. Hi Derek,

      your points are all valid (also see my other post http://www.v-front.de/2013/09/how-to-update-your-standalone-host-to.html).
      We can expect though that this will get better with the next major release of vSphere.



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