MUniversity of Minnesota

September 12, 2003

How much space?

How big should we build the initial server? That is what our server administrator wants to know. More specifically, he wants to know the "expected disc utilization per user." I've asked a few people about this and have never gotten a definitive answer. The following computations are best case scenarios and should not be construed as something we expect, but of something we should be prepared for.

As I've said in previous posts, the U of M community is at least 60,000 users. We feel that a best case scenario is that 1,000 of these people will become users of the system. Let's say that each entry a user makes in the system is 10K in size. Movable Type writes the entry both on a web page and in the database, so that's 20K per person per day. Multiply that by 365 days, and 1,000 users, and you get 7,300,000 KB.

A user can also upload other media, such as graphics. Let's say the typical user uploads 1,000 K per week for their blog. 52 weeks equals 52,000 KB. Multiply this times 1,000 users and you get 52,000,000 KB.

Now, how long do we expect our initial server to last? Let's say 3 years. Technology moves so fast, I don't think it would be wise to go much further out (but I'll leave that decision to the server admin). So, (3 * 7,300,000 KB) = 21,900,000 KB. And (3 * 52,000,000 KB) = 156,000,000 KB. All together that is 177,900,000 KB. That is approximately 170 GB, or about 180 MB per user for 3 years.

I think the expected uploads per week per user may be a little off. And I don't think we'll get anywhere near 1,000 users to start out with. But, as I said above we should definitely be aware of what the potential is. Oh, and somebody please check my math!

Posted by snackeru at September 12, 2003 11:00 AM