I agree with using mod_perl as was previously mentioned. You may also want to look at various Tie'd hashes that pretty much leave the hash on disk, but after tie'ing, the tied hash behaves like any other hash in your program.
Caveat: i am not sure about thread safety with any of the disk bound tied hash modules. If you're just reading info, you're probably ok. If you're modifying data in these hashes, you've probably already dealt with thread safety.