Multiple large databases - what is best practice?

[Peter Simm]

Hello,

As usual with systems which will be "just a small database", my initial effort has grown to 150Gb in disk usage. The project which uses this database is expanding and is now starting another project which will be exactly the same as the existing one, but with seperate data (data structures remain the same).

My question is, what is best practice for adding new databases (which could be 150Gb each, and down the line, could be 2 or 3 of them)? Is it best to:

1/ Add a new database to the current server instance on the same machine
2/ Create a new mysqld process running on another port but on the same server (so as to keep the data distinct and in different ibdata files)
3/ Start a new mysql server on a new machine.

The things I am worried about are performance (eg. will having multiple mysqld processes on the same machine be as efficient as having a single one, will disk IO be a factor - although these databases are report orientated, this is only burst activity initiated by website interaction, fast and reliable data input is more important).

I would be VERY grateful for any opinions or links to websites that you could provide. Knowing what best practice is for this scenario would be invaluable.

Thanks for your help,

Peter Simm