Some days ago I decided to try XenServer instead of the usual ESXi. Initially it was meant to be just a very quick test so I simply used a spare hard drive that I had around, but after a few days I understood that I was going to use XenServer for a while longer (as of now, I am actually thinking about letting go of ESXi for good).
I am a big fan of running servers from USB drives or SD cards, so that’s one of the first things I wanted to do after making the decision to stick with XenServer for a little bit more. Unfortunately, XenServer doesn’t make booting from USB as easy as ESXi: these are the problems I have come across and what I have done to fix them.
You will need 2 USB drives
You will need 2 USB drives (using the same USB drive as both the source and the destination will not work). ESXi allows you to use only one drive since the whole installer is copied in memory, thus allowing you to install on the same USB drive that you have used to boot it.
Get a 16 GB USB drive
The destination USB drive must be at least 16 GB in size (even though the actual space used on the drive will be much less).
I have tried editing the python script that sets the hardware requirements to check for a USB drive of at least 8 GB in size, but installation could not proceed anyway.
The size of the source USB stick does not matter as far as I can tell, as long as it’s big enough to fit the XenServer ISO: to install XenServer 6.5 I have used an 8 GB USB drive.
Local media installation source not found
Once you have booted from USB, you will be asked to select the destination drive, at which point you would select the second USB drive (the 16 GB one). Afterwards, the installer will ask you to choose the installation source: here you will need to select the source USB stick, but for some reason if you select Local media, you will be greeted by a nice error message saying that no local installation media could be found. Interesting, since we have actually used it to get to this point. Anyway, the solution is simple: unplug your source USB drive and plug it again on another USB port. Wait for a few seconds, select Local media again, and this time the installer won’t complain and will allow you to proceed with the installation.