Is your web host overselling?

Overselling is just selling more of something than you have. In the case of web hosting, this typically means promising customers more disk space, or more bandwidth than you can actually provide. Most webhosting companies oversell. This is okay. Say their cheapest plan gives you 250 GB of bandwidth per month. It's such a cheap plan it's not worth selling smaller amounts. But since most personal web sites won't use anywhere near that, you can set your prices even lower, relying on the fact that most people will only use a small fraction of that. It done modestly, you'll never know they did it, but your price will be a bit cheaper.

Now, if your web host massively oversells, the price can be even lower. But your website will sometimes be slower. And if there is a burst of traffic on a different site on the same machine, your website might actually stop working for a little bit. Maybe that's okay, but you should decide to do it intentionally, not because your web host overcommited.

If your web host massively overselling? I can't give you a cut and dry answer. Even if I gave you an answer today, I can't tell you about the situation tomorrow. But I can give you some tools to help figure it out.

First, you need a rough idea what disk space and bandwidth costs. The current Amazon S3 prices are a pretty good baseline. You can get better deals (after all, there is profit in those prices) but S3 is quite reasonable. It's close enough.

At the moment, storage is "$0.15 per GB-Month" while bandwidth is as cheap as "$0.100 per GB."

Let's compare to LunarPages. LunarPages claims to offer "1,500 Gigs Storage" and "15,000 Gigs Data Transfer" for $4.95. We'll just crudely assume that the price only pays for the storage or the bandwidth. It's crude, but good enough for our purposes. So LunarPages is offering storage for $0.0033/GB and bandwidth for $0.00044/GB. LunarPages is selling for about 1/30th of the price of S3. That smells like excessive overselling to me. So long as the overwhelming number of their users only use about 1/30th of what they've been promise everything is okay, but more that and you might start hitting problems. Maybe it's okay, but I don't trust them.

How about Hurricane Electric? (I'm a satisfied customer, so I'm hardly unbiased.) $9.95 a month for 2 GB of storage and 125 GB of bandwidth. That's $4.975/GB for storage and $0.0796/GB for bandwidth. If they're overselling, it's just bandwidth, but only by small amount. That's good enough for me.

(Update later the same day:) I've put together a spreadsheet comparing hosts using this rule of thumb. I can't promise I'll update it, but if I happen to remember I'll try. Yellow cells indicate companies overselling by more more than 10 to 1 which I view as suspicious. Red indicates more than 20 to 1, which I consider outright fraudulent. In each case I've gone for the cheapest plan I could quickly find, but was only willing to commit to a single year up front. It's possible I overlooked some details, but I believe I picked reasonably representative plans. If anyone has recommendations for particularly major web hosts I should add, let me know.

(Later still:) Anyone offering "unlimited" bandwidth is simply lying. I would never buy from such a host. I won't add them to my table because the results are nonsense; they're infinitely overselling.