Linux – Apache crashing; “Too many open files in system”

apache-2.2centoslinux

I am running Apache2 with mpm_prefork on a MediaTemple (dv) server. No significant changes have been made to my server configuration recently. httpd.conf is currently set to the following:

MaxKeepAliveRequests 200
KeepAliveTimeout 15

<IfModule prefork.c>
    StartServers           10
    MinSpareServers        10
    MaxSpareServers        10
    MaxClients            200
    MaxRequestsPerChild   4000
</IfModule>

But I am getting the following error just prior to a full-on apache crash:

[Thu Jun 04 18:30:24 2009] [warn-phpd] mmap cache can't open /var/www/vhosts/mydomain.com/httpdocs/filename.php - Too many open files in system (pid 19873)

I am getting annoyed with babysitting this server to restart it when Apache crashes. Help?

Best Answer

I suggest you try adding a line like this ulimit -n 16384 to the top of file /etc/default/apache2 and then restarting.

Also see this link.

Related Solutions

Httpd – Running out of swap space on web servers, what to do

You're running out of swap because you're using all your RAM and then some. You have a serious problem that you need to rectify right now.

You have two choices: ignore cause and just add more RAM, or target the problem of what's actually munching on your memory.

Adding RAM is fairly cheap and fairly easy if it's your server but it's a temporary fix and if it's a VPS or a rented server, it's not so cheap. Let's have a go at fixing the root problem instead. What's sucking in that much memory? Here are a few tips:

Turn off InnoDB (unless you need it) in MySQL
Beat Apache (and MySQL) with the Stick of Configuration +5
Consider a smaller httpd like cherokee, lighttpd or nginx (they're really fast and eat almost no RAM). Main downside is you can't use .htaccess files but you can hard-code in their functionality.
Are you using an OP-code cache for PHP? Try turning it off or switching to another, more efficient one.

In terms of just getting swap items back into real RAM, you can do that by:

swapoff -a && swapon -a

But don't try then when you've got less free memory than you have things in swap. It'll crash your server.

Linux – Fine tunning of Apache 2 MPM Prefork module parameters

You are going to run out of ram before you will be able to server a Million requests. How large are you apache client processes? I bet over 10MB (probably 25MB). You server could probably only handle 250 clients if the clients were only 10MB.

Might try lighttpd with fast-cgi.

To answer you question you would need to edit the mpm.conf files /etc/apache2/modules.d/00_mpm.conf for me, but im on gentoo so it will be a bit diffrent depending on the distro of linux you are using. But in that config there is a secion for prefork

Here is mine for a server with 12Gb of ram. (and we load balance the sites of 20 identical servers)

<IfModule mpm_prefork_module>
        StartServers            100
        MinSpareServers          5
        MaxSpareServers         200
        ServerLimit             375
        MaxClients              375
        MaxRequestsPerChild      0
</IfModule>

Best Answer

Related Solutions

Httpd – Running out of swap space on web servers, what to do

Linux – Fine tunning of Apache 2 MPM Prefork module parameters

Related Topic