Installing mySQL Database on a new system

[dnamroud]

Hello

I would like to install my MySQL Database file on a new system that I installed...

the only difference is both systems are not using the same version:
the old system is running under 4.0.23-r2 and the newest version installed is 4.1.20

I need to keep the user login/password + data + structure...
My database contians more than 100 GB of data

Can I copy files from oldsystem/var/lib/mysql/* to newsystem/var/lib/mysql or how
Thank you in advance

Dany

[lnxz]

The cleanest way to achieve what you want would probably be to use mysqldump on the old system and restore the dumps on the new one.

[digitalenemy]

on gentoo.org is a good guide for upgrading mysql and how to backup it
http://www.gentoo.org/doc/en/mysql-upgrading.xml

[dnamroud]

Thank you guys for your answers...
one more question:
instead of installing mysql 4.1.20 I will install version 4.0.25, do I need to proceed with the mysqldump...

I am worrying of using this command because it's my first time, and our database is a huge one, I need to keep my Database up and running as I can...

Do you know if there is any big difference in structure between version 4.0.25 and 4.0.23..

thank you a lot

Dany

[lnxz]

The dump itself should be harmless in any case, but you should read the appropriate documentation to make sure that the resulting dump meet your requirements, as there are quite a bit of options to choose from.
I doubt there are any major changes in between 4.0.25 and 4.0.23, but you should check out the mysql changelog if you're uncertain.

[digitalenemy]

you can duplicate the database and do some tests for yourself, before migrating your whole system to it... an other way is to set up a backup or a slave database which replicates itself. this would be a more clean approach if there is no downtime or inconsistency of the database is possible