VMware vSphere 5.1 Hypervisor (Free – ESXi 5.1) Limitations

With the release of VMware vSphere 5.1 many of you are no doubt looking at the benefits it will provide by upgrading your existing vSphere implementation or rolling out a fresh vSphere 5.1 install into your business’s IT production environment.  Check out my earlier post here for details and information on “What’s New” in vSphere 5.1.  As well as production environments, many of you, such as myself, run our own vSphere labs for testing, education and just plain fun (note to self:  must get out more).

VMware vSphere 5.1Many of these vSphere lab environments, due to the cost of licensing, aren’t running fully licensed copies of vSphere with the free vSphere ESXi (aka vSphere Hypervisor) alternative being the preferred option.  But what do the changes to vSphere 5.1 mean for the free ESXi hypervisor?

In the following section I will provide you with a summary of what these limitations are, which will hopefully assist you in deciding whether the free vSphere hypervisor will be sufficient for your needs or whether you should be looking at a paid version of vSphere.

vSphere Free ESXi 5.1 Hypervisor Limitations

Physical Memory Limited to 32GB – Although vRAM has now been removed from VMware’s vSphere licensing model, the free vSphere Hypervisor (ESXi) does contain a physical memory limit of 32GB.  This is pretty generous considering that this is the free version of the ESXi 5.1 hypervisor and that most use cases for this free version of ESXi will be for SMBs and lab environments, both of which won’t likely have a requirement to run an excessive amount of virtual machines (VMs).  The only counter argument to this being that with the increase in CPU power and the reduction in cost of high capacity (eg: 8GB+) memory DIMMs single standalone servers, such as server white boxes are often able to run more than 32GB at quite a low price point, meaning admins/lab enthusiasts are wanting to more fully utilise/sweat their hardware greater than the 32GB memory limit found with the vSphere Hypervisor.

Individual ESXi Host Management Only – This is nothing new as the same applied to earlier versions of the vSphere Hypervisor (ie: free ESXi), though with this free version there is no way to centrally manage multiple instances of the free ESXi hosts via the vSphere Client.  If you have a licensed copy of vSphere vCenter Server in your environment and were wanting to also manage your vSphere free Hypervisor hosts with it, unfortunately this wouldn’t be possible unless you upgrade these hosts to a paid vSphere version.

No vMotion or Other “Nice to Have”/Advanced Features – This point really ties in with the one above, because as there isn’t any vCenter option available with the ESXi free hypervisor you are unable to leverage any of the advanced features that are usually included with most licensed versions of vSphere, eg;

    • vMotion
    • DRS
    • SDRS
    • Fault Tolerance (FT)

Non-Writable API
– The vSphere Hypervisor (free ESXi) doesn’t have a writable API unlike its pay-for-license vSphere counterparts meaning, for example; that the VMs running on the ESXi host can’t be cloned during a VM backup process.  This also means that configuration changes via the vSphere Command-Line Interface (vCLI) are not possible, though you can still use the vCLI for queries.

As mentioned earlier, the typical use case for the vSphere free ESXi Hypervisor is for a standalone ESXi instance used in an SMB or perhaps used in a lab environment where not having some of these more advanced features isn’t necessarily as show-stopper.

It should be pointed out that when you download, install and run an unlicensed (ie: you haven’t applied the free ESXi license) copy of the ESXi host you do get a 60 day trial period where you have access to all the bells and whistles found in the Enterprise version of vSphere.  For those of you needing a short term lab environment for study or product trial purposes then this will likely meet your requirements.  However, if you intended to run the free vSphere (ESXi) hypervisor in your lab environment for longer than 60 days, you should factor in the limitations outlined above.


  1. justsumguy says

    not to mention no Backup API and even Veeam backup is blocked.
    and it looks like you cant use VMA with powerchute to shutdown either.
    essentially its so nutered I wont even use it for my home file server.
    And at 500$ for the essentials pack to get these features…..
    MS hypervisor is more cost effective in a small environment.
    for those that sing the same old VMware song of “MS uses too much overhead”
    I say, CPU, RAM and HDD is way cheaper than VMware licences anyday.

  2. Tomy says

    Hi, can anybody confirm to me if I wont remote shutdown a FREE Esxi 5.1 version using vMA 5 ?? I need to know this because my Boss wants to buy UPS.. (With FREE Esxi 5.0 works).


  3. PICK A NAME says

    another way to extend your 60 days is to shutdown your server when not in use (when using the esx as a try-out server) ; the 60 days – have it all – license does mean 60 days of use, not a start – end date usage.

  4. dp says

    This is correct information, spent 3 hours verifying that 5.1 (free) supports 32gig, 1 cpu. If you purchase VMWare Essentials (approx 450.00 US) then you get up to 1 terabyte of memory but ONLY 2 physicals CPUs. The license is good for 3 physical hosts. Rumor has it that 6.0 (free) will remove memory limits but limit CPUs.

  5. movi123 asd says


    my vmware esxi 5.1 hyperviser consume too much ram when i install windows server 2012..its the only server with no role while in vm it show 1 g.b
    on Esxi 5,1 it shows 6 to 7 gb but in vm it show 1 g.b.. i have install vmware tools also..
    any idea plz ?


  6. Patrick says

    Try the following commands for ESXi 5.1 build 1065491 and 1117900 and 1157734

    rm -r /etc/vmware/license.cfg
    cp /etc/vmware/.#license.cfg /etc/vmware/license.cfg
    /etc/init.d/vpxa restart

  7. nadia says

    vsphere client 5.1 licence finished. i cannot have access to my vm. my esxi pc have not 32 gb of ram. why it’stop?

  8. nadia says

    hi here a follow up… to renew my license of vsphere i have done this on my esxi pc
    rm -r /etc/vmware/license.cfg
    cp /etc/vmware/.#license.cfg /etc/vmware/license.cfg
    /etc/init.d/vpxa restart
    when i logged on my vsphere now, i got the perfect message : now i have 60 days before expiration :-) but when i want to start a vm i got the same error than before : please buy a license!!! what’s the problem? do i need to reboot the esxi? i will try it.


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