Upgrade 5.0.98 to 5.x


I need help, my predecessor has installed percona on one of your servers, but left no manual or whatsoever.
We have a centos 5.9 server (64bit) and need to update/upgrade mysql version. What is the best way to do this?

Update from 5.0 to 5.1.x or from 5.0 to 5.5.x straightaway?

And what are the right steps to do this? I read some articles, but they are all installations from mysqld to percona mysql version.

Preferably our downtime must be as minimal as possible.

Straight away. Just install the newest version, make it use the old data directory, and run the program “mysql_upgrade” that gets installed along with mysqld. That program will update your data files and may or may not run for a long while and causes downtime.

If you want very little downtime, you need to run both versions simultaneously (with different data directories), where the newest version is a slave that replicates the old version. When they are in sync, stop replication and remove the old version.

Thnx for the reply,

Do i have to deinstall version 5.0 first and then a install of 5.5.x? or can i upgrade, if yes how?