Well, I was pretty excited to find out that VMware is now giving away ESXi for free! I have several servers that could benefit from this. While I use Xen in some places, it's only real useful where I have VT-enabled servers so that I can PV & HVM domUs. ESXi gives me the ability to run VMs on some of these others servers where I can't justify purchasing ESX but want the ability to run non-PV VMs.

After spending the past day or so experimenting with ESXi, I've managed to get it to run on some older P4-based SuperMicro servers (SuperServer 5013C-i). ESXi seems to support the SATA ICH5 controllers on these motherboards, so installation is pretty seamless. I've also tried it out on a SuperMicro X5DL8-GG motherboard with less success. First, loading the 7xxx and/or 79xx drivers on this platform fails, even though the motherboard has the on-board Adaptec SCSI adapter (7902, I think). So, on-board SCSI is out. Next, I tried a USB flash drive installation, but this also didn't prove out - the latest BIOS version on this board (circa 2005) still has some issues with USB boot support. I already have a hard enough time with my USB-based KVM switch on this machine, and adding a thumb drive to the mix didn't make the situation any better. So, my only option now is an add-in card supported by ESXi. Problem is that I don't want to spend a lot of money, but most of the chipsets supported by ESXi are "expensive" chipsets, so I need to find a compromise. Also, the chassis has a hot-swap SATA backplane, so a SATA or SAS controller is my best bet. Anyway, I'm sure I'll get that figured out.

Other than that I have a few previous generation Dell servers that may end up running this - a couple of them run VMware Server right now, and a move to ESXi would be a good upgrade, assuming they're supported.