Statistic for requests in deployed VPS servers

Question

I was thinking about different scalability features, and suddenly understand that I don't really know how much can handle one server (VPS). The question for them who have loaded projects.

Imagine server with:

1. 1 Gb Ram
2. 1 Xeon CPU
3. CentOS
4. LAMP with FastCGI
5. PostgreSQL on the same machine

And we need to calculate count of request, so I decided to take middle parameters for app:

1. 80% of requests using one call to db with indexes
2. 40-50 Kb of html
3. Cache in 60% of cases

Add some other parameters, and lets calculate, or tell your story about your loads?

Answer 1

I would look at cacti - it can give you plenty of stats to choose from.