Running vSphere within Workstation will take up a lot of memory…

As some of you noticed, when you install vSphere(ESX) within a VM you will need at least 2GB to get the installer started. Even when it has finished installing you can’t reduce the memory because the following error will occur:

I couldn’t find a way of  pre-adjusting the memory requirements but there’s a way to change this behavior and to downsize the memory when the installation has finished. Keep in mind this is, as far as I know, not supported… it’s only to be used to run ESX within VMware Workstation for your demo / test environment. I personally use it for running 2 ESX servers and vCenter within VMware Workstation on my 4GB laptop. (That’s what I actually use to create screenshots and prepare blog articles.)


  1. Install vSphere(ESX) with at least 2 GB memory
  2. Login to the Service Console and type the following:
    vi /etc/vmware/init/init.d/00.vmnix
  3. Change the following line to the desired value:
  4. Shutdown the virtual machine and change the VMs memory and boot it up!

Thanks Mark for the comment on ESXi:

  1. Install vSphere(ESXi) with at least 2 GB memory
  2. Login to the console via the “unsupported” method.
  3. Edit the file /etc/vmware/esx.conf and add the following line:
    /vmkernel/minMemoryCheck = “false”
  4. Save the file and shutdown ESXi, change the memory and boot it up!

Don’t use any other editor than “vi”, there are multiple reports of nano wrecking the layout of the file which leads to an unrecoverable error during booting.

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    1. Dale says

      Thanks for the tip, I was trying to figure out how to run a couple of test ESX hosts on my laptop for some demos.

      What host OS are you using?

    2. kris says

      wat laptop model is it ? has to be a 64bit and intel vtd or vt right ?

    3. Mark Weaver says

      To adjust memory requirements for vSphere 4i:
      Edit /etc/vmware/esx.conf
      Add line: /vmkernel/minMemoryCheck = “false”

    4. Nils says

      The line about /vmkernel/minMemoryCheck = “false” doesn’t seem to work in ESX4i GA, it complains about being unable to manage filesystems and then just locks up. :(.

    5. Earl says

      I have it running with the GA for 4i you I received a mounting file system error when I used only 1024 gig memory, bumped it up to 1280 and it booted fine.

    6. Bob says

      I tried GA 4i with 1152 meg; it booted but gave a message on Alt+F11 “Not enough memory without swap, system may not be stable”. This message was also there with 1280, 1344, and 1408. It disappeared at 1472. Toshiba Tecra M9 with 4GB of RAM, Win 7 x64 RC, Workstation 6.5.2.

    7. says

      I started with 1280mb but didn’t see any problems until I tried to add the ESX server to VC and it would fail. When I put memory on ESXI to 2048 adding to VC worked fine…then I lowered it back.

    8. djswarm says

      change RequiredMemory to 516096 and you can boot with 768 MB which is barely enough for a minimal xp guest, but enough to vMotion things about.

      You can put the esxi boot image on a usb key, boot to it, make the change, rip it back off with winimage, rezip it and then recreate the iso and not have to sweat installing esxi on minimal machines again, well except for not supporting hardly anything 😉

    9. Ivo Musters says

      started 2x esx4i yesterday with 2GB a piece and vCenter.
      Everything works fine, but it doesn’t leave me any room for booting a VM :S
      changed the esx hosts to 3GB a piece and i had about 1GB free for VM’s (checked by setting resource pool memory reservation)

      4i seems to be taking up the whole first 2GB for itself.
      Checked this article, but can’t find a file 00.vmnix on my esx4i servers…
      There is a 00.vmvisor, but not the file mentioned above.

      Is there any way to change how many mem 4i reserves for kernel ?
      ESXi 4.0.0 build 208167 (Update 1)

    10. says

      By default nano wraps files it edits so you can see their entirety.

      To avoid this behavior, simple start nano with the ‘-w’ flag, and you’re good to go. Long lines now won’t wrap and you can’t ruin a file just by saving it.

      So go ahead, use nano -w file.conf for all your needs.

    11. Jeremiah Powell says

      You can pass the memory check options on the command line when starting up the Installer ISO. On the blue menu that mentions pressing [Tab] for options, press Tab and edit the command line to add the nominMemoryCheck option.

      For a good example with screenshots, see the vmkernel boot options page for ESXi 4.0.

      The boot process appears to get values from /etc/vmware/esx.conf for this command line, so anything you would set in esx.conf may be also provided on boot.

      Unfortunately, the installer seems to eat an inordinate amount of RAM. I’ve had no luck getting the default ISO to run in under 2048 Mb when trying many of the memory control options documented in the vmkernel debugger (press escape at any purple screen and type ‘l’ to access the list.) Perhaps install.tgz needs a diet?

    12. Kevin says

      I am unable to get this memory “hack” to work. I am using Windows 7 x64 and vmware workstation 7. The problem is that I can edit the 00.vmnix file but if the VM on workstation 7 does not get 2 GB allocated my ESX server will not boot. Did anyone else have this problem?

    13. JayH says

      I’m having mixed success.

      The fix for ESXi(using ESXi 4.0.0 U1 Releasebuild-208167):
      adding the line /vmkernel/minMemoryCheck = “false”
      to /etc/vmware/esx.conf
      works fine.

      The fix for ESX(using ESX 4.0.0 U1 build-208167):
      changing RequiredMemory=2064384
      in /etc/vmware/init/init.d/00.vmnix
      has not been working for me.

      Even though the 00.vmnix file is modified (to 1548288, a size of 1.5 GB) ESX stops booting and gives the message:
      “There is not enough memory to load VMKernel. 1572350 KB of RAM was detected. We require at least 2064384 KB of RAM to boot. Aborting boot.”

      Changing the virtual machine settings back to 2048 MB, while leaving the 00.vmnix file at RequiredMemory=1548288, allows the VM to boot – and when finished the title screen displays “2 GB Memory”.
      The VMKernel seems to be disregarding the the change in the 00.vmnix file.

      Did VMware make some changes that are causing the fix not to work?
      Has anyone found a solution?

      Any advice would be appreciated.

    14. Simon L says

      Just did the test with

      RequiredMemory=1032192 (1g of ram)

      And worked well with Workstation 7.01

      Tested with ESX vSphere 4.0 Update 1

    15. says


      I am running the Esxi 4 hypervisor and have made the change /vmkernel/minMemoryCheck = “false” and it has worked. The problem I have is that my laptop has only 2GB or RAM and I need to run 2 ESXi for testing. With 1 ESXi booted running 1096 MB RAM I obviously cant start the other ESXi.

      Problem is I can’t find the /etc/vmware/init/init.d/00.vmnix in its location.

      Is there an equivalent file for ESXi and not just ESX…

      Any help appreciated.


    16. MattG says

      Have been running ESX 4 on 8GB laptop with minimum memory settings without issue. Tried to recreate using ESXi 4 and am having the issue that ivo Munster mentioned which is the when I give ESXi 4 2GB memory it uses it all for itself. It does not leave any room for VMs to startup. I followed the steps in this article:

      And changed the vmvisor’s Reservation to 0. I can start VMs for now. Hopefully won’t cause any major issues.

      Will see.


    17. Chirag says

      Can i install ESX 4.0 with in a VM on VMware workstation 7 running on my laptop.
      Configurations are

      Intel P8400 , 4 GB RAM

    18. yyaazz says

      It looks like, the new 4.1 ESXi does not care about this entry in the esx.conf. Simply goes to PSOD if I give 1,5G ram for example.

    19. yyaazz says

      ok, I’ve tested a bit more. Basically it’s working, but it needs more memory than 4.0u2. 4.0u2 needs 1280Mb and 4.1 needs 1700Mb. With less it gives PSOD.

    20. John says

      Planning to buy a dell laptop. Any supported models to run Vsphere on Workstation 7? Thanks in advance.

    21. Demetrios says

      Quick addition. ESX 4.1 appears to require 1500MB even after performing the file edit listed at the top of the post.

    22. says

      Thanks for the update guys… I never tried it as I bought a workstation with 12GB to make sure I always have enough memory to run at least 3 ESXi VMs :-)

    23. says

      In ESXi 4.1 the option ‘/vmkernel/minMemoryCheck = “false”’ is not only that does not work, it disappeared from the /etc/vmware/esx.conf.

      After the first PSOD I assigned again 2GB of RAM to the ESXi and fired it up and when check the esx.conf file the option was not there. It seems that the system not only ignores it but also fix the esx.conf file and eliminate the new line.

      Later I tried again and the minimum of RAM I manage to run an ESXi with was 1852MB, with less the ESXi VM gave a PSOD.

    24. Habibalby says

      I have added the /vmkernel/minMemoryCheck = “false” in the ESXi 4.1 and reduce the memory to 1700 and it works fine.

      I think i will face the problem only when I add it to the vCenter. But the trick is give more memory, and after added to the vCenter reduce back to 1700MB.

      Any trick to reduce it with less that 1700 MB memory?

      Hussain Al Sayed

    25. Wrightyi28 says

      I edited /etc/vmware/esx.conf and added /vmkernel/minMemoryCheck = “false” and also edited /etc/vmware/init/init.d/00.vmnix changed the value to 516096. Booted with 2GB to begin with this worked then messed with different VM memory settings 1GB does not work but I can use 1.5GB. I am running Windows 7 Enterprise x86 with 4GB RAM and Intel Core i3 Processor.

    26. CM says

      I can boot with 1600 MB configured on Fusion 5.0.1 …
      But the esxi 5.1 show 1.7 GIB …