Coding Horror just had an article about moving his site to a new host running as a virtual server. I’ve got to say, I’m starting to become a big fan of this. When I was looking for a web host, as soon as I realized it was even an option, I started looking exclusively for a virtual private server. I get almost all of the benefits of a dedicated server without the price (although, I must say, there are some really good deals available for dedicated server hosting as well). I can install any software I want, configure it any way I’d like, and not have to go through a “control panel” app. to do it. It includes a Win 2003 Server license, so I don’t even have that expense.
The biggest limitation I’ve found is hard drive space. Most VPS solutions just don’t give you very much space. I’ve got 6 GB available on my site. While that’s not too bad, I would have preferred quite a bit more (15 GB would have been great). Once you start adding space, though, the monthly price starts ratcheting up (I think it’s a bit out of line for the value – thankfully 6 GB is something I can live with). I get 200 GB/month of bandwidth and 3 dedicated IP addresses. It runs $40/month, which isn’t too horrible. I’m guessing they must be hoping to get 5-10 VM’s per machine. That would seem to fit for a 72 GB drive w/RAID and the min. dedicated stats of 384 Megs of memory and 200 MHz of CPU. A fully loaded box that all had a lot of traffic might be a little sluggish – thankfully I don’t think the box I’m currently on is anywhere near that (at least yet).
I’ve found the performance to be pretty reasonable. Of course, the VM for my site is idle most of the day so I’m not really pushing it <g>. Jeff’s site generates a huge amount of traffic; he had more visitors in a few seconds than I’ll get in a day (take a look at his traffic stats which are available as a link off the main Coding Horror page). When I was looking it appeared most VPS solutions are limited by the bandwidth per month available, 200-300 GB/month on average (a few sites offered more but had terrible reviews). At his level (maybe 2000GB/month based on the estimate someone posted of 5.7 Mbit/sec of traffic) I’d be tempted to want to just go with unmetered hosting (and once you hit that level, you’re really going to want to be on a dedicated box). There seems to be a bit of a margin here from various hosts (unmetered vs metered), so I guess YMMV.
Of course, there is nothing keeping you from then running a virtual server on your dedicated box. There is something really attractive about being able to just take a snapshot of the VM image and drop it on a new box if you need to scale performance (or run multiple copies of the image on a few boxes). Or, imagine your host running into connectivity issues. You could just take the VM image and move it to a backup host really quickly.
One huge thing to consider is the price of virtualization on performance. I found a really interesting article that went more in depth about it. Cliff notes version – he saw an approx. 40% performance hit on the total requests that a machine can handle. That may kill any fantasies about virtualizing a server for some of you <g>. But, like most things, there are tradeoffs which may still make it an attractive alternative.
Links
http://www.codinghorror.com/blog/archives/000984.html http://www.webperformanceinc.com/library/reports/LoadTestingVirtualizationPerformance/ http://www.galaxyvisions.com