work with other databases. Personally, I'm going to see how much work is involved in porting the code to MySQL, since I don't use Postgres.
Both are good, MySQL is single threaded and perfect for most web applications. Postgres is multi threaded and significantly faster, especially if you use a persistent connection. BerkleyDB is also pretty incredible, but sometimes cryptic to work with. You may want to discover Sybase 11.0.3, which is free for Linux even in commercial production applications. Incredible lookup speed on large databases.. For a DNS server: Ram is cheap. Last thing I learned about doing database driven DNS: Keep multiple versions of code and data handy. You may induce a glitch that instead of fubaring a single domain/record, blows the whole server in nanoseconds. My tertiary server is several iterations behind my primary and secondary for this reason.