Installing Percona Server 5.5 on Ubuntu 10.04 Lucid

Installation

Debian and Ubuntu packages from Percona are signed with a key. So before using the repository, you should add the key to apt. To do that, run the following commands:
gpg --keyserver hkp://keys.gnupg.net --recv-keys 1C4CBDCDCD2EFD2A
gpg -a --export CD2EFD2A | sudo apt-key add -
Add the following lines to '/etc/apt/sources.list':

deb http://repo.percona.com/apt lucid main
deb-src http://repo.percona.com/apt lucid main

If you are using some other distribution, then you can substitute your distribution name with 'lucid'. To get the name of your distribution you can run the following command:

cat /etc/*-release

This command will show you the distribution information. Your distribution name will be the value of 'DISTRIB_CODENAME'

Now update the local cache:
apt-get update

To install Percona Server 5.5 use the command:

sudo apt-get install percona-server-server-5.5

Kudos! Percona Server 5.5 will now be installed.

Note: Percona Server 5.5 does not come with a default configuration file (i.e my.cnf). To figure out where you can put my.cnf file your need to run the following commands:
which mysqld --> /usr/sbin/mysqld
/usr/sbin/mysqld/ --verbose --help | grep -A 1 'Default options'
The output will be some lines. Among those lines you will see text like 'Default options are read from the following files in the given order: /etc/my.cnf /etc/mysql/my.cnf ........'. You can put the 'my.cnf' file in any of these directories but make sure that there is no config file in the directories that will be looked up before the directory you choose, else your my.cnf file will not be read. I personally prefer putting the 'my.cnf' file in '/etc/mysql/my.cnf'

In order to force MySQL not to run automatically when the server starts run the following command:

sudo update-rc.d -f mysql remove 
You will now need to start MySQL manually when you start or reboot your server.

Some post-installation notes and points

Using a custom data directory and log directory for MySQL:

I generally put MySQL data files on a RAID-10 array and MySQL log files on a logical volume (No RAID configuration), so I explicitly mention data and log directories in the 'my.cnf' file. Below is how i specify MySQL data directory and MySQL log file directory:

Under  [mysqld] 

# data file directory
datadir = /var/mysql-data 

#log file directories
log_error = /var/mysql-logs/mysql-error.log
slow_query_log = 1
slow_query_log_file = /var/mysql-logs/mysql-slow.log
general_log = 1

general_log_file =  /var/mysql-logs/mysql-query.log  

Now if you do something like this, you need to keep somethings in mind. 

If you change the 'datadir' to a location other than MySQL's default data directory, you need to move folders 'mysql' and 'performance_schema' from '/var/lib/mysql/' to your new data directory. You can use the following command:

sudo mv /var/lib/mysql/mysql /var/mysql-data

sudo mv /var/lib/mysql/performance_schema /var/mysql-data

Note: Make sure the folder '/var/mysql-data' or whatever folder you are using as MySQL data folder has the right owner. That is owner should me 'mysql' and owner group should be 'mysql' too. You can change the owner using the following command:

sudo chown mysql:mysql /var/mysql-data

The same instructions apply to MySQL log folder, in-case you decide to use a different folder to store the log files.

Using a custom location to store 'socket' and 'pid_file'

Suppose you want to specify a custom location to store MySQL's socket and pid like in the configurations below:

Under [mysqld]

socket = /path/to/mysql/mysql.sock
pid_file =  /path/to/mysql/mysql.pid
Under [client]

socket = /var/lib/mysql/mysql.sock 

Make sure you have the right ownership of the folder containing both the files (mysql:mysql). Secondly, you also need to alter the 'debian.cnf' file which you can find in '/etc/mysql/debian.cnf'. Open 'debian.cnf' file and change the 'socket' location to the location you set in 'my.cnf'. If you do not do that, MySQL fails to start and stop.

Start/Stop/Restart MySQL

To start/stop/restart MySQL using the following command:
service mysql [start or stop or restart]
or 
/etc/init.d/mysql [start or stop or restart]