MySQL won't start!

"Check your log files as in the other answers. Also, check that you have enough (or any disk-space). MySQL can behave in this way on an empty partition.

df -h

If it's not that, check out MySQL's docs on debugging a server. Their myisamchk (if you're using MyISAM) is particularly useful."

Take a look at your log files. On Debian at least, you get mysql* logs in /var/log.

Had this same problem, turns out the solution was staring me in the face. The drive was full. You get no logs because there is no where to write them.....

"The same problem plagued me for ages on an Ubuntu 12.04 Digital Ocean VPS with mysql 5.6 installed from a PPA. The symptoms were the that the mysql.sock file at /var/run/mysqld/mysql.sock would get removed but never recreated, so I was having to manually run the following commands every time mysql was updated or the server rebooted:

sudo touch /var/run/mysqld/mysql.sock
sudo chown mysql /var/run/mysqld/mysql.sock

This was from Kyle C's answer (except with mysqld instead of mysql). In the end I downgraded to mysql 5.5 which comes when you would normally perform a sudo apt-get install mysql-server command. However it wasn't straight forward so here is what I had to do:

# Manually get mysql running if it is not
sudo touch /var/run/mysqld/mysql.sock
sudo chown mysql /var/run/mysqld/mysql.sock
sudo service mysql start

# take a dump of all databases
# we are going to remove the mysql files so don't skip this)
mysqldump -u root -p > all-databases.sql

# Completely remove mysql
sudo apt-get remove --purge mysql-server mysql-client mysql-common
sudo apt-get autoremove
sudo apt-get autoclean

# Remove mysql 5.6 from debs (otherwise it will reinstall 5.6)
rm /etc/apt/sources.list.d/ondrej-(mysql something please check)

# remove a flag that would prevent the installation
# because it is seen as a downgrade
sudo rm /var/lib/mysql/debian-5.6.flag

# I had to remove the mysql files as well
# reference http://ubuntuforumsdotorg/showthread.php?t=1998260&page=3
rm -rf /var/lib/mysql
rm -rf /etc/mysql*

# Install mysql
sudo apt-get install mysql-server mysql-client mysql-common php5-mysql

# manually update the all-databases.sql file and
# remove all STATS_PERSISTENT clauses on table creation statments

# re import the databses
mysql -u root -p < all-databases.sql

# restart apache
sudo service apache2 restart

# at this point my wordpress site stated error connecting to database.
# This was resolved by logging into mysql and running:
FLUSH PRIVILEGES

Hopefully this will help someone else having the same pain."