script to determine if server is maxed out?

sneakyimp

Can anyone recommend a php approach to help me determine if my server is maxed out? Me and a friend have created a site on a dedicated server that has seen steadily increasing traffic for almost exactly a year now and I'm starting to wonder how close it might be getting to its limit.

There is a file that includes all the critical application definitions that gets run on almost every page access. I was thinking of putting something like this in there:

// 1 in 100 chance...
if (rand(0,99) == 0) {
  $str = passthru('w');

  // then parse the results to determine server load
}

The problem is, I'm not sure what part of the 'w' results are more relevant or what threshold is too high.

Other things I don't know: Where is the bottleneck (if any)? Is it the disk drive? I need more RAM? faster CPU? Clustering?

Any help would be much appreciated.

hagen00

This might not be a very useful post, but i'll post nonetheless...You could always get onto your server during peak time, when you usually get the most traffic and just run "top" and see how much memory and CPU is being consumed...I don't think you necessarily need a PHP approach to determine whether your box is maxed. If it's slow, and top verifies that, then it's maxed...

The first thing I would do is whack more RAM in. Servers like RAM.

MarkR

Don't use passthru('w')

You should really have some monitoring stuff. The easiest way is to get Apache to measure the response time of requests (Read the Apache stuff about logging - you can report on this in microseconds easily).

You could easily make a shell script which runs "w" (or uptime indeed) every few minutes and logs the results. Run this under "screen" or similar.

Don't set MaxClients higher than you have enough RAM for (Normally this means under 50). Don't set MaxClients higher than the maximum number of MySQL connections.

If you're using Apache in prefork mode on Unix, consider changing it for worker (threaded mode) to save RAM.

Consider using a PHP compiler / cache such as APC, eaccelerator or the zend one (but test it thoroughly in dev first!).

Mark