Optimizing server for "alot of requests"

[haringsrob]

Hi,

I'm starting a new project and this website (written in php) is doing the following:

Every second on every client connected it does a post request to the server requesting some data (20products, price, current time).
Also every minute a cronjob runs (wich checks for every second during the cron if there have been changes).
Every night at 00.00 every product gets updated and paused until the morning (no trafic then).

Everything runs smooth atm, I have tested up to 20 connections at once, Ajax requests stay below 100ms.

Howevery I think the server runs to its most requests/sec/apache pid's etc.

Question is:

What can I do to allow more connections?
What can I do to optimize the server for this website?

I'm allready caching as much as possible and minimizing my query data/mysql query's in my code(1/user/second is not much!).

Server details:
Centos 64Bit
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
3GB memory
Apache 2.2.22
DirectAdmin 1.39.3
MySQL 5.5.14
Php 5.2.17

Edit: I'm both the developer and Server maintainer

Friendly greetings.

 

[zEitEr]

Hello,

Just some ideas:
1. 3Gb is not that much nowadays.
2. Replace apache with nginx. Or switch to Front-end+Back-end scheme of using Apache+Nginx
3. Mount /tmp as tmpfs
4. PHP opcode?
5. Watch your server and tune it continuously.