Something to be said for having a sys admin? =) Let's see if I can clear some things up:
In Reply To:
I didn't realise that each of them behaves like it's own independent server and eats a chunk of memory for itself
No, not true. You have only one apache, and it handles all the domains on the machine. You could have 5,000 and be ok as long as none of them got much traffic. =) It's all about the number of hits the combinded total of your domains get, not the number of domains you have.
In Reply To:
Mem: 127068k - Used: 113232k - Free: 13836k
I'm assuming linux here, but having 13k free is ok. Your operating system will cache frequently requested information into memory and so it will appear there is very little memory free, but this is ok. What you want to watch out for is that you are not using any swap. For instance on our server we have:
Code:
total used free
Mem: 517052 490440 26612
Swap: 393584 3660 389924
So while we only have 26MB out of 512MB free, this is ok as the memory is all being utilized caching frequently requested information. You don't want to see anything significant being used in swap though (as this means pulled from disk). If you are swapping, then it's time to go out and buy memory (actually it was time a couple days ago, you shuold never get to swapping on a web server).
In Reply To:
When sorted into Memory order, the httpd's (I assume that's the virtual host deamons?) are as follows:
3508, 3460, 3456, 3456, 3408, 3404, 3380, 3372, 3364, 3360, 3332, 2960, total: 40460
The way Apache works is it has one process that runs as root, and then spawns several other processes that handle all the incoming requests. So if you see 10 or 15 httpds, a lot of them are just sitting around waiting for requests. You can tweak this setting by editing httpd.conf.
Also, a lot of that memory is shared, so the total memory used by Apache is not the sum of those numbers, but something quite a bit smaller.
As for mod_perl, you don't want to run it as the main webserver, but rather as a proxied web server. It takes a bit of playing around with it, but is worth it once setup properly. =)
Cheers,
Alex
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