Hello

I was wondering if there was a way to do an upgrade from mysql 4 to 5 on a live production server, without more then 10secs downtime.

Obviously I know the procedure would be something like this:

1. download mysql source to all servers
2. compile with same flags on all servers
3. shut down slave 1, restart slave 1 with new version
4. repeat for each slave
5. shutdown master and restart with new version

The big BUT in the above is that MySQL dev site says one should "Dump all data from the old version and import it in the new version" which is completely unrealistic on a live production server with hits in the 1M range every day, our service is mission critical and so is our database.

This is one of the things I have to get absolutely right from the first try or get set back for hours, possibly days, which is complete and utter taboo.

Comments, thoughts, anyone?


Thank you

Rather you than me

Firstly are you running INNODB, if so, how big are the innodb files?

Just thinking it may be worth thinking about rebuilding the master on another box, import the data into the new version, set it up as a slave, ensure that it is behaving properly as a slave, when you are sure it is, make this box the master.

Take the master down, upgrade it set it up as a slave to the new temp master make sure it is behaving correctly, then make the original master the master again. More work, but less downtime (unless your INNODB files are massive, which would mean a bit of downtime while copying them across).

Ass about elbow, but that should work, just a lot of steps to make sure that you do not get wrong, but at least you ensure and maintain data integrity by effectively doing the upgrade on the live data on an offline environment.

Just a few thoughts.

The same would apply to the slave, only you would have to have MASTER - SLAVE - TEMP SLAVE, so that you could upgrade the SLAVE as well.

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This advise is given -as is- without warranty of any kind, either expressed or implied.

It is assumed that you have at least one verified backup before following any of the instructions above.

Funny as is it, we only have MyIsam tables in use, total size about 40G. . .