Getting my existing forum set up

Number of simultaneous users doesn't mean anything. What matters is how often your users make HTTP requests (req/s), and how much resources it takes to handle each request. A lightweight CMS with good caching can handle upwards of 100 req/s even on the 512MB plan. A heavy CMS with bloated plugins will struggle to pump out 10 req/s even on the 4GB plan. Every website is different, so the only way to figure out is by trying. If you configure everything properly, there's no reason a forum with 200 simultaneous users can't be run on a single 512-768MB server.

Lightweight web servers such as nginx can serve static files to hundreds of users with virtually no server load. So unless your site is really big, you probably won't benefit from using an additional server for static files. Maybe it'll make a difference if you used a third-party CDN for static files, but otherwise don't bother. If you really want to use more than one server, put the DB on its own server. That makes a lot more sense that putting static files on its own server, because the DB actually generates considerable load. But managing additional servers is also a lot of work, so I'd suggest that you stick with one server for the time being, perhaps a 1GB node if you want to be comfy. If you need more resources, upgrading only takes a few minutes. The whole point of "cloud" hosting is to purchase only as much resources as you need, right? Don't waste money on resources you don't need.

Control panels are generally considered to be a waste of resources unless you're running your own web hosting business.

CentOS is commonly used in the web hosting business because it is compatible with RHEL and integrates well with cPanel. Here at Linode, it seems that most people use Debian and Ubuntu instead. The latter is supposed to be more noob-friendly, although even that is a largely a matter of preference. (I personally prefer Debian, but only because I'm used to it.)

When you choose an OS version, you should look carefully at the version of the scripting language (usually PHP) that your forum uses. Some CMS's are only compatible with PHP 5.2. Most others work well with PHP 5.3.

Thanks hybinet :)

Is there any benchmarks I could pull from my current host to gauge what my requirements would be if I switched to linode? This is my site(www.the-sps.org), the front end can be a bit heavy, what do you think?

What I will do to begin with before I even attempt the move is order 1 node tomorrow, I'll try and get it up and running with a test installation/clean copy of the forum software. It'll be a tall order for me. If I can get that up and running and I'm confident enough then I'll consider adding an additional node and split out the DB to one.

I doubt that there are any such benchmarks. Also, this is the first time I even saw a ZenForo forum. What's with all these proprietary forum packages these days?

As a rule of thumb, any site that performs tolerably on a $9.95 shared hosting account (or a £9.99 "cloud") will probably perform just fine, if not much better, on a properly configured $19.95 Linode – not to mention a bigger plan. Even the smallest plan here often has better CPU than most other "cloud" offerings out there.

But again, the only way to be sure is to test. Don't use a clean copy of your forum software. Make a copy of the entire site and the database, load it up, tweak MySQL settings, and test it under realistic conditions. For example, you can use simple tools like "ab" to measure the performance of your front page.

Thanks again, you really do your research. I've got a node now and will have a play throughout today :)

I don't think you really need four linodes, especially not if you're new at Linux; you'd be much better off with a single larger linode. It'd be so much easier to manage.

JEEZ,

I'm finding this really difficult. I'm following the centos5 lemp guide, ultimately I don't know if I've set everything up correctly. I'm using the following domain www.the-sps.net

Hmmmmm as far as I can tell everything should be good to go. I've got to the stage now that I've uploaded files to www but when I try to access anything I get a 404 nginx error.