What kind of performance can I expect from a 384K connection for a site that has mild E-Commerce and forums?
it depends... some data centers will allow you to burst your speed if the overall usage average is less than 384k... I forget the math involved in figuring out how much data that is, but if you can burst you should be good.... although at a limit of 384 they might only let you burst to 1mbps instead of 10 or 100. I make sure about the bursting rules prior to putting a server in a data center. Colocation makes sooo much more sense than getting a T1 or fractional T1. A T1 is great for outbound internet access, but it doesn't meet needs for hosting a web server. Another thing to think about when colocating is the cost and the brand of bandwidth. Some places sell bandwidth dirt cheap, but it's oversaturated and unreliable. Others have cheap quality access, and others have quality access they'll charge you up the ying yang for. I have two data centers I would recommend: rackmy.com <- a little more expensive ($5/gig) and hostingandcolo.com <- (if you let them know you want quality bandwidth they'll put you on mzima bandwidth for a little more than their advertised cheap rates)
I'm running 2 dozen+ sites on a 384K up connection, doing right around 800-1000 uniques a day. When you add it all in - uniques, repeats, and bots, I'm doing about 3000 hits a day and about 8,000 page views. Upon occassion, I load one of my sites from work to see. No problems so far.... In theory, 384K means it can throw up a 100K page in 1/3 of a second. Or 3 pages a second. Works the averages out on that and you can do 180 a minute, ~10,000 and hour, or about 250,000 page views a day. If you' hosting php or asp pages doing database calls, I'd expect performance problems from your web or database server before you'd start having a bottleneck throwing up the pages. I'd focus on optimizing your code, especially if you're doing DB calls, and keeping the pages small and tight. I'm keeping an eye on things. To be on the safe side, if my max pages per minute ever hits 90 fairly consistently (half the theorectical max for an average 100K page size) I'll look at making the jump to the next tier, which, for my service, is 512K up. BTW, I run a forum for SFReader off that connection. Busy enough for a science fiction forum, but that means a dozen or so posts a day, maybe 10 simultaneous lurkers.... no one has ever complained that it's slow.
My initial thoughts where more in line with iShopHQ's. Here's what Dell says to expect... http://dell.bandwidth.com/tools/knowledgeBase?page=dellIcView&icid=50
It's fine... you would be surprised how little bandwidth you need. This forum averages about 120kbits and never peaks above 250kbits. I have more bandwidth available of course, but just telling you what the traffic charts show. If there were a ton of graphics and stuff, that of course would be different. I've also done what I can to make the pages small (external CSS, mod_gzip at the server-level, etc.)
My interpretation of that is you can do 10-20 simultaneous users on your 384. Bearing in mind that someone loads a page, looks at it a moment, and then loads another. Chances of pages being accessed at the exact same time for 10-20 users is probably pretty slim. Even so, in theory, if 3 people click on links at the exact same time, the web server receives the requests at the exact same time, and your pages are 100K, it should still only take 1 second or so for all the code to be transferred. And before someone speaks up about how slow the images load on my site, that's because I'm running a server side imaging component to resize the images vendors are serving me. My site is actually going out, gets the image from the vendor site, brings it back, resizes it, and then serves it up to the visitor. And some of the vendors out there are serving 400x400 images as large as 75K - on some pages I'm getting and resizing 10 or more of them!