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Rufus takes seconds to create a bootable USB flash drive for ESXi installation

Rufus takes seconds to create a bootable USB flash drive for ESXi installation

Mar 12 2015 11:15am EDT update – with ESXi 6.0 now released, worth noting that Rufus still works just fine, including the new but very similar Rufus 2.0 Portable.
Rufus: Reliable USB Formatting Utility (with Source), read the introductionFAQ, and support forum.

There are many Windows utilities out there that’ll help you create a bootable flash drive from your ISO image, normally used for creating CDs or DVDs.

This article is only focused on quickly and easily making a flash drive boot the ESXi installer, so you can then install ESXi onto this same flash drive. Cool, eh?

There are many methods I’ve used to create bootable media for ESXi over the last decade or so. All had some drawbacks, including the need to pay very close attention to command line diskpart commands. I was seeking something quicker and easier, and I’ve settled on Rufus recently, which has the following advantages:

  • free
  • simple GUI
  • can be run from an EXE that doesn’t require any installation
  • doesn’t require careful attention to command line partitioning commands that can be a bit dangerous
  • much faster than other methods, takes under a minute to follow my instructions below
  • seems to work, every time, back on Windows XP, right through Windows 8

For folks used to installing Windows or Linux on hard or solid state drives, it may come as a surprise that there’s little reason to install your hypervisor there. Why? Well, wear isn’t really the issue (explained below). It can be very handy in a lab to be able to shutdown the server, then simply remove and replace the USB flash drive with different USB drive with a different hypervisor. Say, for beta testing. Or testing different VIBs. This swapping allows you to leave all the internal hard drives as-is, datastores for VMs. This is geared toward the home lab enthusiast. In datacenters, the various server vendors often has specific recommendations for certain USB flash devices.

As long as you boot the ESXi installer from your USB flash drive, then choose that same flash drive as the ESXi install target, it’s all pretty darn simple and fast. All the other hard drive data remains untouched. VMware can actually install on any flash drive that’s 1GB or greater in capacity, explained at the blogs.vmware.com here:

1.  What size USB/SD should I use?

The minimum disk size required to install ESXi is 1GB. When booting USB/SD there is little benefit to using a larger device because any space beyond the 1st GB will go unused.  When choosing a USB/SD boot device, it’s not the size of the device that is important but the reliability of the device.  Be sure to use good quality USB/SD devices.

2.  How long will a USB/SD device last?

Unlike a local disk or SAN LUN, USB/SD devices are sensitive to excessive amounts of I/O as they tend to wear over time.  This naturally raises a concern about the life span of the USB/SD device. When booting from USB/SD keep in mind that once ESXi is loaded, it runs from memory and there is very little ongoing I/O to the boot device. The only reoccurring I/O is when the host configuration is routinely saved to the USB/SD device, which by default is done once every 10 minutes.  Based on how often you reboot  the host and install patches it is expected that a good quality USB should last for several years.

Since the USB drive is mostly just read at boot time, the speed of the hypervisor is not held back at all, once the boot is done. You can even get Microsoft Hyper-V to install on a 8GB USB drive as well, read more at Microsoft TechNet. Probably makes most sense for the GUI-less variant of Hyper-V.

So, why wouldn’t you think of using USB drives for ESXi, especially now that many server motherboards having an on-the-motherboard USB socket these days? Well, one barrier was Windows folks getting scared off by VMware’s Format a USB Flash Drive to Boot the ESXi Installation or Upgrade that required Linux, causing them to simply burn a CD or DVD of the install ISO. Then along came this little gem of a post from Kent Chen, on using Rufus, on July 2013, How To Format A USB Flash Drive to Boot VMware ESXi 5 Installation on Windows, along with RobWillis.info video.

There are many methods I’ve used to create bootable media for ESXi, including the methods outlined below that each have some significant drawbacks and dangers.

Over the years, having had to deal with this issue in my home lab quite often, and I’m quite glad to share this super fast fix for re-using USB flash drives (thumb drives, USB sticks, etc.), with these advantages:

  • simple GUI
  • can be run from an EXE that doesn’t require any installation
  • doesn’t require careful attention to command line partitioning commands that can be a bit dangerous
  • much faster than other methods
  • seems to work, every time, back on Windows XP, right through Windows 8

Here’s the 4 minute video outlining the actual 2 minute procedure to create the USB flash drive with the ESXi 5.5 installer.

, then follow the step-by-step instructions below.

double-click-to-launch-the-.exe-you-downloaded
double-click to launch the .exe you downloaded
User-Account-Control-say-Yes
‘User Account Control’ say Yes
Just-close-the-Update-policy-and-settings-dialogue-a-new-feature-in-Windows-8.1
Just close the ‘Update policy and settings’ dialogue
Rufus-update-policy-Do-you-want-to-allow-Rufus-to-check-for-application-updates-select-No
‘Rufus update policy’ ‘Do you want to allow Rufus to check for application updates’ select No
chose-your-ESXi-ISO-image-file
choose your ESXi ISO image file
Replace-menu.c32-say-Yes
‘Replace menu.c32’ say Yes
WARNING-ALL-DATA-ON-DEVICE-YOUR-DEVICENAME-WILL-BE-DESTROYED-click-OK
‘WARNING ALL DATA ON DEVICE [YOUR DEVICENAME] WILL BE DESTROYED’ click OK
When-bottom-left-says-DONE-click-Close
When bottom-left says ‘DONE’ click Close
Remember-to-safely-eject-the-USB-device-when-youre-done-with-it
Remember to safely eject the USB device when you’re done with it. You do do that, don’t you?

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