yet another apache2 tuning thread

[falko]

There are spikes in disk latency and disk usage for /dev/sdb. Maybe there's something wrong with the drive?

[Ovidiu]

thanks, I saw that. but postfix was busy sending out a huge newsletter and the HD always gets that busy during that period without crashing everything.

since I moved to this new server just a few months ago, I assumed the HDs were ok...

I'll run the Strato HW test again tonight, makes the server unreachable for two hours but at least I'll know if there is something wrong...

btw. that server runs on a software raid1 that came pre-installed on the minimal debian OS they offer. anyone has any links for raid optimizing? any parameters to tune? I haven't touched it yet...

[erosbk]

Maybe this could help you...

http://rimuhosting.com/howto/memory.jsp

[Ovidiu]

thx, there are a few nice tips in there, will see if it helps figure it all out...

[Ovidiu]

didn't have time to check the HDs yet, but here we go again:


|-amavisd-new---2*[amavisd-new]
|-apache2-+-50*[apache2]
| |-apache2---60*[php-cgi]

swapping like crazy.

top with M pressed: http://screencast.com/t/P4m7xKvs8

everything is soooo slow :-(

###edit###
managed to dump some info here: http://pastebin.com/qErr4PjE - does that help?

[erosbk]

Are you using prefork or worker? Could you post your apache2.conf

[Ovidiu]

using prefork.
config is here: http://howtoforge.com/forums/showpos...9&postcount=14
did restart apache and it became a bit better and more responsive...

still need to figure out whats going wrong here.

[erosbk]

Backup your apache2.conf, make this changes:

MaxKeepAliveRequests 100
KeepAlivetimeout 15

<IfModule mpm_prefork_module>
StartServers 2
MinSpareServers 2
MaxSpareServers 3
MaxClients 45
MaxRequestsPerChild 500
</IfModule>

I am not an expert, but as I can see apache2 is eating all your memory... I don't know your entire configuration and if this could or not work for you. But I think that you must limit the resources destinated to apache, in order to evade swap (and lack of memory... see what happen in four or five days, your memory will not be enough if you let it as it is right now).

Try to see if it works better or not than before. Take note of memory consumtion and memory consumption incrementation curve (more slow? more quickly?). If you note any change, it is just a setting problem with this directives. If this not work, you always can rollback the conf file.

Restart apache2 this night, it was recently restarted, so... it must be running ok right now.

Regards

[Ovidiu]

not sure if your settings will help.
I see you want me to start fewer children and limit the maxrequestsperchild but it doesn't look like some script has a memory leak as I don't have a few apache children with high memory consumption, I have heaps of them...

default KeepAlivetimeout is 5 - why set it higher? that will tie my ressources down even more :-(

still, giving some of your changes a try.

thanks

[erosbk]

What I want is to isolate you problem (not to find the exactly settings). If you can manage to do that, next you know where to work (if you have changes after this, you can see if you have problems only with apache, or with other process, or whatever)

When I am blind about a problem, always worked for me to discard little pieces one at a time.

I give special atention to your case, I will use debian with apache2 in production server in a few days, finding a solution for you will be great for me too. I will keep working on your problem.

Right know, in my test server, with just 2 test sites with almost no traffic, my ram consumption has growth from 340mb to 1.4gb max in 2 days (with no swaping because I have 4gb ram).

I think that apache2 debian package is not prepared out of the box to host vhosts... we will see for your health and mine :P

Regards