How would I go about this?

I have a ton of grouped pdf files that I need to store in such a way that I can read and search them in the fastest way possible. Write/Annotate/Delete times are not important.

* The pdfs are already grouped by various themes and alphanumerically. This should facilitate searching.

* Average file size is about 2MB.

* There are about 2.5M files

How would I go about this?

Fucking easy

Install Google Desktop Search
Point it to the folder with all the PDF's.
Wait a day for GDS to index all that shit

PROFIT!

If you want, there's a Python command line tool that you can use to interface with GDS.