Because of dependencies, you cannot install Percona Server alongside MySQL from the repositories, this will be a manual install if you want separate instances or remove MySQL first. Once the binaries are upgraded you should run mysql_upgrade.

How long it takes to complete mysql_upgrade is hard to tell. If that 8GB are mostly InnoDB, then much of the work will be table checks,

Percona-Server includes XtraDB, this is the drop in replacement for InnoDB - you do not have to do anything to you InnoDB tables. After the upgrade your InnoDB tables will actually be using XtraDB. Hint: SHOW ENGINES

Since you are able to spin up a testbed: this will be your best first step so you have an idea of what it takes completely to do the upgrade.

Hi Thanks for your help.

I decided to run the upgrade on our slave server after taking a full backup so that I could restore if needed.

First step I removed mysql and then ran sudo apt-get install percona-server-server-5.5

I encountered issues after installation but analysis of the logs showed that I needed to comment out some unsupported entries in /etc/mysql/my.cnf
skip-bdb was the major culprit.

After this mysql started and I ran mysql_upgrade -u root -p
This upgrade took around 1 hour 20 minutes on a cloud machine with 256MB of RAM.
The first part of the upgrade was very quick but then it ran out of RAM and crawled along.

Next step is to test and schedule an upgrade for the master server.

I had thought it was all working but replication doesnt want to start.
I had previously commented out the replication lines in my.cnf
Uncommented to start the slave and mysql fails to start.
Comment them again and it works.
When checking the syslog I spotted an error at the end of the upgrade despite it reporting OK in the terminal.
Logs below.


Aug 31 06:17:50 mysql2 /etc/mysql/debian-start[1078]: Running 'mysql_fix_privilege_tables'...Aug 31 06:17:50 mysql2 /etc/mysql/debian-start[1078]: ERROR 1370 (42000) at line 1111: alter routine command denied to user 'debian-sys-maint'@'local$Aug 31 06:17:50 mysql2 /etc/mysql/debian-start[1078]: ERROR 1044 (42000) at line 1112: Access denied for user 'debian-sys-maint'@'localhost' to datab$Aug 31 06:17:50 mysql2 /etc/mysql/debian-start[1078]: ERROR 1370 (42000) at line 1125: alter routine command denied to user 'debian-sys-maint'@'local$Aug 31 06:17:50 mysql2 /etc/mysql/debian-start[1078]: WARNING: NULL values of the 'character_set_client' column ('mysql.proc' table) have been update$Aug 31 06:17:50 mysql2 /etc/mysql/debian-start[1078]: WARNING: NULL values of the 'collation_connection' column ('mysql.proc' table) have been update$Aug 31 06:17:50 mysql2 /etc/mysql/debian-start[1078]: WARNING: NULL values of the 'db_collation' column ('mysql.proc' table) have been updated with d$Aug 31 06:17:50 mysql2 /etc/mysql/debian-start[1078]: FATAL ERROR: Upgrade failedAug 31 06:17:51 mysql2 /etc/mysql/debian-start[1271]: Checking for insecure root accounts.Aug 31 06:17:51 mysql2 /etc/mysql/debian-start[1277]: Triggering myisam-recover for all MyISAM tablesAug 31 06:30:33 mysql2 /etc/init.d/mysql[15254]: 0 processes alive and '/usr/bin/mysqladmin --defaults-file=/etc/mysql/debian.cnf ping' resulted inAug 31 06:30:34 mysql2 /etc/init.d/mysql[15254]: ^G/usr/bin/mysqladmin: connect to server at 'localhost' failedAug 31 06:30:34 mysql2 /etc/init.d/mysql[15254]: error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)'Aug 31 06:30:34 mysql2 /etc/init.d/mysql[15254]: Check that mysqld is running and that the socket: '/var/run/mysqld/mysqld.sock' exists!Aug 31 06:30:34 mysql2 /etc/init.d/mysql[15254]:Aug 31 06:31:16 mysql2 /etc/init.d/mysql[15823]: 0 processes alive and '/usr/bin/mysqladmin --defaults-file=/etc/mysql/debian.cnf ping' resulted inAug 31 06:31:16 mysql2 /etc/init.d/mysql[15823]: ^G/usr/bin/mysqladmin: connect to server at 'localhost' failedAug 31 06:31:16 mysql2 /etc/init.d/mysql[15823]: error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)'Aug 31 06:31:16 mysql2 /etc/init.d/mysql[15823]: Check that mysqld is running and that the socket: '/var/run/mysqld/mysqld.sock' exists!Aug 31 06:31:16 mysql2 /etc/init.d/mysql[15823]:Aug 31 06:34:29 mysql2 /etc/init.d/mysql[16394]: 0 processes alive and '/usr/bin/mysqladmin --defaults-file=/etc/mysql/debian.cnf ping' resulted inAug 31 06:34:29 mysql2 /etc/init.d/mysql[16394]: ^G/usr/bin/mysqladmin: connect to server at 'localhost' failedAug 31 06:34:29 mysql2 /etc/init.d/mysql[16394]: error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)'Aug 31 06:34:29 mysql2 /etc/init.d/mysql[16394]: Check that mysqld is running and that the socket: '/var/run/mysqld/mysqld.sock' exists!Aug 31 06:34:29 mysql2 /etc/init.d/mysql[16394]:Aug 31 06:35:25 mysql2 /etc/mysql/debian-start[16780]: Upgrading MySQL tables if necessary.Aug 31 06:35:25 mysql2 /etc/mysql/debian-start[16784]: /usr/bin/mysql_upgrade: the '--basedir' option is always ignoredAug 31 06:35:25 mysql2 /etc/mysql/debian-start[16784]: Looking for 'mysql' as: /usr/bin/mysqlAug 31 06:35:25 mysql2 /etc/mysql/debian-start[16784]: Looking for 'mysqlcheck' as: /usr/bin/mysqlcheckAug 31 06:35:25 mysql2 /etc/mysql/debian-start[16784]: This installation of MySQL is already upgraded to 5.5.12, use --force if you still need to run$Aug 31 06:35:25 mysql2 /etc/mysql/debian-start[16795]: Checking for insecure root accounts.Aug 31 06:35:25 mysql2 /etc/mysql/debian-start[16800]: Triggering myisam-recover for all MyISAM tables