I’ve deployed a number of VMware installations for clients and have been reasonably happy with the results. I recently spoke with someone who advocated using Xen for GNU/Linux servers and Windows Virtual Server for Windows servers. I would agree that in an exclusively GNU/Linux environment that Xen is my preferred solution. However, most of my clients need both Windows and GNU/Linux servers and I would prefer them to be hosted on the same server. I also think it’s advantageous to use only 1 virtualization solution for an organization, especially smaller organizations. At home I’ve been using VirtualBox OSE (even though I’d qualify for the full version under the Personal Use license). I’ve been considering why it might be a better choice than VMware for businesses.

I’ve been meaning to write about this for a while and since it’s come up recently (Write Intent Bitmaps, Software RAID) I figured now would be a good time. Basically what the write-intent bitmap does is keep track of which blocks are being used so that in the event that a resync is needed (power failure, kernel crash, disk temporarily offline) only the blocks that are out of sync are copied. This drastically improves resync times. Of course there is a downside.