We bought a Dell R620 to run VMware ESXi 5.1U1. It was pre-configured to correctly boot the supplied ESXi image from an SD card. Bringing it up on the network was trivial. Downloading the Windows vSphere Client software was trivial. Configuring a datastore so that you could actually use the product was annoying.

Y’see, they shipped it with a Windows GPT partition table, and attempting to use the disk produced a lengthy timeout and disconnect, every time. Occasionally, I’d get a pop-up error message, but couldn’t select it to cut and paste, and enabling ssh on the server showed that no errors were being logged.

Typing the error message in by hand (“… HostDatastoreSystem.QueryVmfsDatastoreCreateOptions … failed”) and googling it turned up detailed solutions for the problem, with obsolete commands. So, for the benefit of anyone else who gets into this state on ESXi 5.1:

1. Enable ssh, and log in as root.
2. Run esxcli storage core path list, locate your disk by the display name that showed up in the vSphere Client, and save the contents of the Device: field (mine was naa.6b8ca3a0e8405800195f77a21641467c).
3. run partedUtil mklabel /vmfs/devices/disks/device msdos

Now you can use it as a datastore.