January 6th, 2010 
Kiwi Si 
Since writing my original post last year on installing VMware ESXi 3.5 onto a USB memory stick things have changed and with the release of vSphere VMware have now provided an official method of doing this which is much easier than any of the previous ‘unofficial’ methods. As such I felt compelled to write an updated post giving easy to follow steps to assist in instructing how to create such a bootable VMware ESXi 4.0 USB memory stick.
It’s almost so easy that I don’t need to provide any screen shots showing how to do it but what the hey – here they are anyway. 
1. The first thing you’ll need is a spare USB memory stick. For this I am using a generic 2GB Dane-Elec (never heard of them before but they were cheap from my local Staples store) memory stick. I usually go for a 2GB memory stick as I know it will have ample space for the installation.
2. The next step is to download ESXi from VMware here and burn if off onto CD.
3. Now insert the USB memory stick into a USB port which is able to be booted (eg: internal USB port) – though at this stage make sure that your server can boot from the CD/DVD drive.
4. Insert the CD containing the ESXi install into the servers CD/DVD drive and boot or restart the server.
5. Upon booting off of the VMware ESXi installation CD you will be presented with the screen below – press the ‘Enter’ key. Also, notice the option to ‘Repair’ an ESXi installation from this screen by pressing the ‘R’ button. This is useful when you have a corrupt ESXi installation and you wish to reinstate a fresh install – this option is non-destructive to the /vmfs/volume on your ESXi host which may contain your VMs, etc though you will lose your host’s configuration settings.
6. Sign your life away to VMware by pressing the ‘F11’ key.
7. At this stage you will see a list of all your storage devices connected to your VMware ESXi host – select your USB memory stick and press ‘Enter’.
8. If your USB memory stick already has data on it you will be asked if you definitely want to continue with writing ESXi down to it. This is to avoid any accidental mishaps. Press ‘Enter’.
9. Next press ‘F11’ to confirm the installation of ESXi onto the USB flash drive.
10. Sit back and wait whilst ESXi is written down to your USB flash drive – at this point you should see it flashing away (assuming it has an LED activity light). This install process generally only takes a couple of minutes.
11. Once the installation has completed you will receive the screen below. At this point remove the ESXi installation CD from the servers CD/DVD drive and press ‘Enter’ to reboot the server.
IMPORTANT: Upon the server rebooting ensure that its boot priority order is set so that the USB port(s) are booted from first.
Your server should now be booting successfully off of the USB memory stick to VMware ESXi 4 – all you need to do now is configure it!
Although being pretty straight forward I hope you found this of use.
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Posted in 
My name is Simon Seagrave and I am a London (UK) based Senior Technology Consultant and vSpecialist working for EMC. 
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Hey Simon, Happy New Year to you
Good stuff, much simpler than the WINRAR, WinImage method
Cheers
Craig (VirtualProUK)
[Reply]
Kiwi Si Reply:
January 6th, 2010 at 6:03 pm
Hi Craig,
Happy New Year!
I agree, much neating than the old WINRAR, etc methods – why couldn’t they of had this with ESXi 3.5, lol.
All the best,
Simon
[Reply]
Happy New Year Simon,
Crikey you have been busy with lots of new posts already for 2010.
I was wondering if it is possible to backup the USB key configuration of ESXi by making copies of the key once you have completed the configuration? Have you done this?
Cheers
LW
[Reply]
Hey, Simon…Another great tutorial, but I have one question. (For those that read this, I am a VMware newbie!) WHY would you want to run ESXi from a USB key? I am assuming to save disk space, but isn’t it only 32MB for the install? I guess I don’t see the advantages cause I am just starting to learn about all the cool things that VMware can do.
[Reply]
Kiwi Si Reply:
January 7th, 2010 at 12:57 am
Hi Michael,
Definitely a good and sensible question! The following are some reasons why I’d choose to install and run VMware ESXi from a USB key or SHDC memory card (HP Proliants) as opposed to local disk:
- No local disks on the ESX(i) host: Enterprise level servers such as the HP Proliant BL490c (Intel) or BL495c are geared towards virtualization and so as to maximize physical memory space in the servers case it doesn’t come with internal disks. For these servers a hypervisor such as ESX(i) can either be booted from SAN (though this is only experimental at this stage for ESX(i)) or booted from a USB memory stick or SHDC memory card. That said, the only servers that tend to be diskless are blade servers. So if using rack mount or floor standing servers why bother you may ask…
- More space on local disk: By installing and running ESXi from a USB memory stick you have 100% of any local disk for ISO storage, or if not using shared disk space via a SAN or NAS appliance then you can use all or part of this local disk space to run your VMs from. But as you correctly mention the actual footprint of an ESXi installation is actually quite small (ie: just under 1GB for ESX 4.0) leaving plenty of local disk space available. With the capacity of modern disks (eg: 74GB+ minimum) the space it consumes is something of a non-issue. This particular point is a little hard to argue though for me personally I like the flexibility in my lab environment of keeping my ESXi install and any local disk storage used for ISO’s or VMs separate. This means I can easily pull out one USB memory stick containing a version of ESXi and insert another containing a different version within seconds without impacting any ISOs files or VMs. To do this with a disk based ESXi install is much more hassle.
- Remote Site Deployment: If you are sending a server to a remote site direct from a supplier then it is easy to post/courier out a pre-configured USB memory stick containing ESXi complete with the ESXi configuration all set up and have someone with little or no IT skills plug it into the server to get things up and running. A typical scenario would be a site with a limited network connection to allow the administrator to connect to the server via ILO or DRAC to install (eg: using virtual media) and apply the configuration.
There are probably more reasons but these are the main ones that spring to mind.
All: If anyone can think of any please add a comment.
Hope this helps.
Cheers,
Simon
[Reply]
Simon,
Nice tutorial. I wanted to also point out a few posts on VCritical related to ESXi and USB flash:
http://www.vcritical.com/tag/usb-flash/
Eric
[Reply]
Kiwi Si Reply:
January 6th, 2010 at 6:08 pm
Hi Eric,
Thanks for calling by – some good ESXi/USB posts on your site there. I inparticular like your post that discusses the size of the ESXi foot print – http://www.vcritical.com/2009/08/if-vmware-esxi-4-is-so-small-why-is-it-so-big/ and the ESXi 64MB challenge – http://www.vcritical.com/2009/08/the-vmware-esxi-4-64mb-hypervisor-challenge/
I recommend that others check out these out – interesting reading.
All the best,
Simon
[Reply]
Some advice on setting up VMFS volumes would be great. After briefly trying ESXi, I went back to Hyper-V, as I find the way it handles partitons and VHDs much easier to understand.
I would like to switch to ESXi, and be able to over-commit memory and have multiple VMs access storage on a clustered file system, etc, but I just cannot figure out how to actually set up the vdisks for the VMs and data.
[Reply]
Kiwi Si Reply:
January 6th, 2010 at 11:59 pm
Hi,
Thanks for the reading TechHead. Are you meaning how to present usable vmfs disk storage (eg: local disk or a NAS or SAN appliance) within ESXi?
Cheers,
Simon
[Reply]
Quick question. Let us assume I have 1 usb based ESXi Host (being managed by vCenter Server). Is there a “quick” way of creating/configuring a second host (on identical hardware) by cloning 1 USB drive? (My 2nd ML115 is already set to boot from USB).
rp2000
[Reply]
Hi
You wrote in your article:
“Also, notice the option to ‘Repair’ an ESXi installation from this screen by pressing the ‘R’ button. This is useful when you have a corrupt ESXi installation and you wish to reinstate a fresh install – this option is non-destructive to the /vmfs/volume on your ESXi host which may contain your VMs, etc though you will lose your host’s configuration settings.”
If I have an existing ESXi 4 install on my local HD and I select the “install” option is this destructive to the local vmfs datastore?
Thanks
[Reply]
Hi guys, i am using ESXi 3.5 right now, booting from a USB stick. I use two SATA disks. Can i format the USB stick without any problem to put version 4.0 on it? And how get i the datastores of the disks back in 4.0?
[Reply]
Kiwi Si Reply:
January 9th, 2010 at 12:09 pm
Hi Bart,
Are you using vCenter Server or are you managing the ESXi host by connecting to it directly using the client?
I would recommend, if possible, that you first back up your VMs first in the unlikely event there are any problems.
I’m guessing that all of your VMs are on the two SATA disks – in which case you have 4 options in upgrading to vSphere (ESX(i) 4.0):
1. Use the VMware Update Manager (VUM) to upgrade your ESXi host – though for this you need to be running vCenter Server and have another ESX(i) host. If doing this remember to always upgrade your vCenter Server installation before upgrading any of your ESX(i) hosts.
2. Use the VMware Host Update Utility from another server or PC to upgrade your ESXi host.
3. Power down your ESXi host and using the ESXi 4.0 installation CD upgrade your USB key (make sure your point the ugprade at your USB key and not your 2 x SATA disks).
4. Install ESXi 4.0 onto a seperate USB memory stick and then swap it out for the one in your ESXi 3.5 host.
Note: Options 3 & 4 above will not maintain any of your ESXi settings – so you will have to set up everything.
All options will allow you to reconnect to your SATA storage. Options 1 & 2 will maintain your information about any connected VMs and with options 3 & 4 you will need to (within the vSphere client) goto the data store (ie: 2 x SATA disk) and re-add the VMs back in by right mouse clicking on the vmx file of each VM and selecting ‘Add to inventory’.
Once you have upgraded your ESXi host to 4.0 you will also need to upgrade your client (vSphere client).
Hope this helps.
Cheers,
Simon
[Reply]
Bart Reply:
January 9th, 2010 at 1:23 pm
Hi Kiwi,
I am using ESXi 3.5 on a ML 110 G5, connecting to it with the vi client. At the download page of VmWare i don’t see a upgrade file, only a full iso-file?
[Reply]
Kiwi Si Reply:
January 9th, 2010 at 1:28 pm
Hi Bart,
If going for option 3 or 4 which I mentioned then you will need to download the full ISO install of ESXi 4.0.
Cheers,
Simon
Bart Reply:
January 9th, 2010 at 1:30 pm
And if i want to go for option 2? The Upgrade Utility is seeing the machine, but asks for a ZIP-file for the upgrade.
Hi Simon Seagrave
Your articles just have an amazing quality, its very rare to see a similar compilation with so nice reading (jokes and relation content) with technical support.
Just a dilemma, i tested the all the 3 ways, but the winimage method, described in:
http://www.techhead.co.uk/how-to-create-a-bootable-vmware-esxi-usb-pen-drive
was the fasted, because basically you only need to extract the VMware-VMvisor-big-208167-x86_64.dd and “burn” it to pendrive with winimage.
It was the most effect way that i tested to inject OEM drivers in ESXi, very very easy and more particle than the XYZ methods out there. (just replace the oem.tgz with drivers in partition0) i love to see my Realtek 8169 PCI Gigabit NICs drivers working perfectly with it.
So the question is, what is the best method?
I prefer the winimage because i can replicate it fast in many pen drives that i want and is the easiest and fasted method to inject OEM drivers.
[Reply]
Kiwi Si Reply:
January 9th, 2010 at 1:27 pm
Hi Andre,
Thank for reading TechHead and for the kind feedback – much appreciated.
I agree, if you want to slipstream/insert additional drivers into your ESXi source files I personally think that the WinImage method is the easiest. If wanting to perform a standard and supported ESXi install I would go for VMware’s ‘official’ installation method.
All the best,
Simon
[Reply]
looks nice i will try it, thanks for sharing
[Reply]
I have an interesting question (I hope)…I installed ESXi4 to one of my 8Gb USB thumbdrives, but later replaced it with a 2Gb USB thumbdrive and went to remove the files from the 8Gb drive to use it for something else and I noticed that my thumbdrive’s filesystem had been flashed in a way that I could no longer remove the created partitions and even worse…my 8Gb drive is now only 4MB in size…that’s MEGABYTES! yikes. Even when I went to Windows Disk Management, I was not able to modify or delete any of the 4 or 5 partitions that were created and the 6.5 Gb of unallocated space is no longer accessible.
Have you seen this problem and have a suggestion on how to fix it? If I can’t fix this, then I pretty much have a trashed thumbdrive courtesy of ESXi.
Thanks!
Jeff
[Reply]
rp2000 Reply:
January 21st, 2010 at 3:57 am
Hi mate,
I have seen similar stuff with this on systems that use Linux/Unix. Basically they “partition” your disk differently to windows. Windows systems use MBR (Master Boot Record) and other systems use GPT (GUID Partition Table). In actual fact your USB disk is probably 4 GPT partitions, but windows is only reporting the 1st in disk management (And I bet when you right click options to format/concert etc are unavailable).
Use “diskpart” in msdos to fix this via command line. Googling should give you the answer/syntax/commands and solution quickly. Off the top of my head you either need to use the “clean” command on your USB drive or the “Convert to MBR” commands (syntax is not exact, but google it). Be careful as DiskPart utility does not give you many warning messages and you do not want to mess up any disks in your physical windows machines.
It is late now, and I am only replying because my gmail alert went off!! If it is not resolved post here again or e-mail me on @gmail.com (first bit is my posting name here) and I will try to help, but it is really straightforward to fix.
rp2000
[Reply]
Ben Reply:
July 22nd, 2010 at 5:08 am
In my blog I just wrote about how to fix a flash drive when it only appears to have 4Mb of space after installing VMWare ESXi.
You can check out my answer here: http://www.benwagner.net/computing/vmware-esxi-flash-drive-only-4mb/
[Reply]
Hi Simon,
Thanks your articles are excellent and very helpful.
I managed to install ESXi 3.5 using form your site and now i am using ESXi 4 with help from your site.
Hopefully this will be helpful when I go on my Vsphere course at the beginning of March.
Thanks very much
Pat
[Reply]
We have also installed ESXi 4 onto a flash drive, does anyone know if we should be backing up the flash drivesomehow?
Repeated read/write operations will cause a USB stick to fail – is it actually reading/writing to the stick whilst the OS is running? (no light on our flash drive so cannot be sure)
Thanks
[Reply]
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