If you have a /var partition, and if that partition is too small it may fill up quickly. If you want to move the data which is stored in “/var” to another partition, run the following:
du | sort -n
This will give you a full readout of all the directories that are using the most space. The directory using the most disk space will appear at the bottom of the list.
One common culprit is mysql (/var/lib/mysql on Redhat). To move that path to another partition, run the following:
chown mysql:mysql mysql
/sbin/service mysqld stop
cp -Rp /var/lib/mysql/* .
mv mysql mysql_old
ln -s /home/mysql ./mysql
/sbin/service mysqld start
#once satisfied that mysqld is running, remove the old data:
rm -rf mysql_old