Enable innodb_file_per_table

innodb_file_per_table is by default ON Mysql 5.6.6 and onwards. There is plenty of stuff on Google about pros & cons ofinnodb_file_per_table.

This post details how to enable innodb_file_per_table on an existing database. Because innodb_file_per_table affects new tables only, created after innodb_file_per_table is enabled, we need to recreate old databases to force innodb_file_per_table on old tables and reclaim some disk space.

Backup First

Create a dir to take backups:

cd ~
mkdir backup
cd backup

Copy mysql data files (raw)

If all goes well, we will not need this.

For better results, shut down PHP and other apps/scripts which update mysql. You can keep Nginx running and server non-logged in visitors cached content.

service mysql stop && cp -ra /var/lib/mysql mysqldata && service mysql start

Take mysqldump

As soon as above line completes, take a mysqldump of all databases

mysqldump --routines --events --flush-privileges --all-databases > all-db.sql

Drop Databases

Create a sql file to drop all databases EXCEPT mysql database

mysql -e "SELECT DISTINCT CONCAT ('DROP DATABASE ',TABLE_SCHEMA,' ;') FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA <> 'mysql' AND TABLE_SCHEMA <> 'information_schema';" | tail -n+2 > drop.sql

Verify if drop.sql has correct database names and then execute drop.sql queries.

mysql < drop.sql

Verify all InnoDB tables gone

SELECT table_name, table_schema, engine FROM information_schema.tables WHERE engine = 'InnoDB';

Remove InnoDB files

Stop mysql server first

service mysql stop

Then

rm /var/lib/mysql/ibdata1 && rm /var/lib/mysql/ib_logfile0 && rm /var/lib/mysql/ib_logfile1

At this point most likely you will have only /var/lib/mysql/mysql directory only.

Enable innodb_file_per_table

Open my.cnf file

vim /etc/mysql/my.cnf

Add following lines

innodb_file_per_table = 1
innodb_file_format = barracuda

Time to import from mysqldump

Start mysql server now

service mysql start

Run mysql import

mysql < all-db.sql

Force mysql_upgrade (to generate performance_schema)

mysql_upgrade --force

That’s All!

Script:

#!/bin/bash -x

if test "$USER" != "root" ; then
  echo "Must be root ..."
  exit 1
fi

mysql_dba=root
mysql_pass=your_mysql_dba_password

mkdir /var/lib/mysql.bak
cd /var/lib/mysql.bak
service mysql stop && cp -ra /var/lib/mysql mysqldata && service mysql start
mysqldump -u$mysql_dba -p$mysql_pass --routines --events --flush-privileges --all-databases > all-db.sql
mysql -u$mysql_dba -p$mysql_pass -e "SELECT DISTINCT CONCAT ('DROP DATABASE ',TABLE_SCHEMA,' ;') FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA <> 'mysql' AND TABLE_SCHEMA <> 'information_schema';" | tail -n+2 > drop.sql
cat drop.sql
mysql -u$mysql_dba -p$mysql_pass < drop.sql
echo "SELECT table_name, table_schema, engine FROM information_schema.tables WHERE engine = 'InnoDB';" > innotables.sql
mysql -u$mysql_dba -p < innotables.sql
service mysql stop
rm /var/lib/mysql/ibdata1 && rm /var/lib/mysql/ib_logfile0 && rm /var/lib/mysql/ib_logfile1
cp -p /etc/mysql/my.cnf /etc/mysql/my.cnf.date +%Y.%m.%d.%H.%M.%S sed -e 's/([mysqld])/\1\ninnodb_file_per_table = 1\ninnodb_file_format = barracuda /' /etc/mysql/my.cnf > /tmp/my.cnf mv /tmp/my.cnf /etc/mysql/my.cnf service mysql start mysql -u$mysql_dba -p$mysql_pass < all-db.sql mysql_upgrade -u$mysql_dba -p$mysql_pass --force # eof