What database works best for installation
The best answer for that is probably "it depends". It depends on how much content, how many concurrent users, what operating system you're using, ...
That said, our Moodles run on Ubuntu and I use MariaDB. MySQL works equally well. I have no experience with other supported databases though others on this list do.
+1 to what Bret said! and that's from CentOS 5 and 6 and RedHat Enterprise 5 and 6 boxen. Just make sure it's 64 bit version.
'spirit of sharing', Ken