So continuing in the vein of trying out these virtualization options in the marketplace I looked into the big gun - VMware to see how that would go on my cheapernetwork. Alas, my attempts were doomed to fail. The initial installation of ESXi failed - it was unable to detect the hard disk drives in my HP virtual servers. It was a bit of a WTF moment - that a fairly easily available mainboard, with no special interfaces or anything like that. The disks were fairly standard SATA disks - Seagate drives both. 160GB so not small and not unusually large. At any rate, after trying different disks, going to the console prompt and looking there I gave up. dmesg didn't even detect the /dev/sdi disks at all and the more I investigated the more I found that there were some hardware limitations. Given I have limited time, I abandoned my VMware attempts and instead looked into Oracle's Virtualization offerings.
The first thing that struck me was the sheer size of the downloads for the components of Oracle VM - it's a complex system, needing not only your head units (my HP desktops in this case) but also another PC as the manager - with an install of Oracle Linux required, plus the over 2GB VM Manager and then I needed two NFS shares for more data. In terms of complexity compared with XenServer I was surprised. I could install the VM Manager as a virtual machine on another host ( I decided to use my notebook running VMware player - which I love by the way). I had downloaded the netboot option for Oracle Linux - trying to minimise the impact on my corporate network. None of this went smoothly of course. VMware Player ran fine, the Oracle Linux install needed a URL to install from - and this proved surprisingly hard to find. I spent a bit of time searching for it, but the Oracle install information I found was for Oracle Linux Release 5, not 6 and very little information was available - perhaps my google-fu was letting me down... At any rate, again - time was against me. I had to let it go for the time being.
The thing that has struck me throughout this exercise is just how easy it was to get XenServer going - Citrix are really on to something. Additionally, for supported platforms under the XenServer virtual platforms it is silly easy to transfer guest machines between hosts - right click - move to server and off it goes. The downtime is extremely small. If you pay for XenServer you can enable High Availability so guests can be restarted on host fail and you can really start to get some high uptimes. If you know that the box is about to fail - it's trivial to migrate them around - fantastic!
So we'll keep playing with XenServer for the time being and with a bit of luck I can re-visit VMware down the track.