James Andres's Tips & How-To's

Hello Web-travlers and welcome to my new site. I’ll have some fresh content shortly, once I sand smooth all the rough edges on the site.

Until then, I’ve posted a few of the better posts from my blog on projectopus.com.

While you wait, why not check out the site in

/[e]?l(i|y)nks/

?

James.

This is an old post originally taken from my blog on Project Opus

Yea, I finally got around to reading about what the MaxClients variable in the apache2.conf is for. Please keep your laughter to yourself, but i thought what MaxClients meant was “how many clients can connect at one time.” So logically, I set it at 255. Well, I’m not sure if MaxClients is a cryptic name, or maybe I just missed the boat, but actually this variable controls how many server processes will run simultaneously!

Visually stated: MaxClients == MaximumNumberOfApacheInstancesRunningAtTheSameTime

So what? Well, when load got high, apache would start spawing “hefty” Drupal processes @ between 20MB and 80MB each.

Simple math: 255×60MB = 15,300 MB RAM usage (hint: we don’t have 15 GB of RAM)

As you can see this is a bad situation.

I changed the nubmer to 40 this morning and systems haven’t been happier :-)

Lessons learned … lessons learned

James.

This is an old post originally taken from my blog on Project Opus

Hello all,

Off-Topic Note

I’ve decided to start blogging on a bit more of a regular basis. I’m not much of a blogger, but who knows … it might just stick this time. I have a hunch problem was subject matter. So from now on I plan to stick to what I know best. Geek stuff!

Main Feature

Just learned an interesting thing about APC (the popular PHP opcode cache) today: APC hates SMP. I’ve been trying for nearly a month to get APC to run stably on our multi-CPU system. Invariably the extension will start seg. faulting within a few minutes or hours of starting up.

After many headaches, I gave up on APC. Running PHP without an opcode cache is a fairly crazy thing to do, so for the last month I’ve been looking high and low for a replacement. Recently I just stumbled across XCache and immediately loved what I saw. XCache is very similar to APC, the installation was nearly identical, but it has a few added options (I haven’t explored them all yet).

Best of all, it works great with SMP!!!

XCache Introcution Page ... before then I had used APC. Although it was quite stable for a php4 with flock() configuration it had become unstable once I upgraded my server to a dual cpu (4 threaded cpu) because it flock()ed badly so XCache was used instead and seems to have solved the problem.

I couldn’t have said it better my self.

James.