upgrade mysql server with least downtime

[Patrick Hsieh <pahud@pahud.net>]

Hello list,

I am planing to upgrade a running mysql server on woody to fix the recent 
security issue. Is there any trick to make the service have least downtime 
when upgrading the mysql server?

I was thinking if it is possible that I have two mysql daemons running on the 
same machine(port 3306 and 3307) and share the same mysql data. When I 
upgrade the 1st daemon, the iptables redirects the incoming tcp 3306 
connection to tcp 3307, on which the secondary daemon is listening. When 
finish upgrading, change the localhost iptables rules to dismiss the 
redirection. Is it possible? Will I have locking problem with 2 daemons 
sharing the same mysql data?


Any idea is highly welcome.