99.5% Uptime Guaranteed. I’m supposed to be happy?
I don’t know why I never bothered to do the math on this one before. I guess mainly because anytime people are talking about “a sure thing” but that they don’t have implicit control over, they say something to the effect of 99% guaranteed, or 99.5%, or even 99.9%. Or in Ivory’s case, 99.44%.
Here’s the problem with using this guarantee for web hosting. 99% uptime sounds like a lot, and it certainly does mean mostly up. But with 24 hours in a day, it takes only four days, plus four hours to equal 100 hours, the easiest point from which we can do our math.
That means every four days, a webhost guaranteeing you 99% uptime has it in their every right for your site to be inaccessible for an hour. I don’t know about you, but if my site was down for one whole hour every four days, I’d be pretty ticked, and shop for a new host. So let’s do that, let’s move to someone with a better guarantee: 99.5%
With 99.5% uptime, we’re floating at half an hour down every four days. Still enough to make me upset--undoubtedly if it really did happen every four days. That’s down nearly four hours every month. Can we do better? Well, a current host we are using claims 99.9% uptime guaranteed.
Wow, sounds great, right? 99.9% uptime! That’s only six minutes down every four days, or 45 minutes per month, 9 hours per year! Oh but wait, there’s a problem. There’s no way that that’s going to happen. First of all, this host specifically can’t do that. We’ve had two outages in the first week of March alone. (Sitting at 96.2% uptime right now, thanks to SiteUptime.com.) And that hardly allows for even scheduled maintenance, adding hardware to the network, or any other number of legitimate reasons for the servers to be taken offline.
Back to the 99.5% uptime: Yes, if they do it every four days, it would be irritating and probably cause for alarm. However, that only allows for two days of downtime per year. I suppose some good hosts can actually meet this, but in my experience, that’s not even something that a host can do. Of course, your bills aren’t dependant on them meeting this percentage annually, but monthly.
My conclusion? Look at your hosts’s uptime guarantee. Is it 99%? That’s pretty lenient for them. Almost 8 hours a month. If you don’t notice it, don’t worry about it. Is it 99.5%? If they’re hitting that mark, cheer. Is it 99.9%? This is where you need to be scared. Even the best of hosts don’t have a hope of meeting 99.9% uptime. It’s not in the cards. If your host advertises this, it’s because they are trying to make it look like they are one-upping the competition. And it’s a good dipstick to gauge that other claims on their site are probably equally exaggerated, distorted, and out of the realms of physical possibility for them to provide you with.
Posted Tuesday March 9, 2004 in Web Development by Derek Jones
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