MySQL for Low RAM applications

Posted by admin on Jun 19th, 2009 | no comments home title

The point of this article is to demonstrate how to install and optimise Lighttpd, PHP5 and MySQL under Debian (My system runs ‘Etch’).

If you feel I’ve missed anything in this article, or have made an error, get in touch.

Ok, so let’s grab lighttpd, php and MySQL

apt-get install lighttpd php5-cgi php5-cli php5-mysql mysql-server

You may want to add any other php modules that you may require, such as php5-curl, php5-gd etc.

Next, as lighttpd automatically assumes you’re using php4, we need to update the fastcgi php path in:

/etc/lighttpd/conf-available/10-fastcgi.conf

Look for the line

"bin-path" => "/usr/bin/php4-cgi",

and replace it with

"bin-path" => "/usr/bin/php5-cgi",

Simple.

While you have the file open, change

"max-procs" => 2,

and

"PHP_FCGI_CHILDREN" => "2",

This will reduce the number of waiting fastcgi instances, thus reducing ram. If you have a particularly busy site, you may want to either leave this, or perhaps even increase it.

Now enable fastcgi module in lighttpd

lighty-enable-mod fastcgi

Restart lighttpd

/etc/init.d/lighttpd restart

You now have lighttpd running perfectly with php5.

You might now want to add some virtual hosts. For example purposes, we’ll call these foo.com and bar.net

Create your directory structure:

mkdir /home/sites/foo.com
mkdir -p /home/sites/foo.com/http
mkdir -p /home/sites/foo.com/logs

mkdir /home/sites/bar.net
mkdir -p /home/sites/bar.net/http
mkdir -p /home/sites/logs

Give ownership of the logs directory to the web server

chown www-data /home/sites/foo.com/logs
chown www-data /home/sites/bar.net/logs

Once we’ve done this, we can sort out the config side of things.
Open up

/etc/lighttpd/lighttpd.conf

Include the configuration files you’ll use for each of your domains

include "foo.com.conf"
include "bar.net.conf"

Now open up

/etc/lighttpd/foo.com.conf

and add

$HTTP["host"] =~ "foo\.com" {
server.document-root = "/home/sites/foo.com/http"
accesslog.filename         = "/home/sites/foo.com/logs/access.log"
}

and the same for

bar.net.conf

$HTTP["host"] =~ "bar\.net" {
server.document-root = "/home/sites/bar.net/http"
accesslog.filename         = "/home/sites/bar.net/logs/access.log"
}

Again, restart lighttpd

/etc/init.d/lighttpd restart

and you’re done.

For MySQL

I simply altered some of it’s fine tuning values.
Open

/etc/mysql/my.cnf

and change the following values

key_buffer              = 16K
max_allowed_packet      = 1M
thread_stack            = 64K
thread_cache_size       = 8
#max_connections        = 100
table_cache            = 4