Not only that, but he fails to grok the reason for there being a limit with the database size on 32-bit systems. It's directly a result of MongoDB using memory

Not only that, but he fails to grok the reason for there being a limit with the database size on 32-bit systems. It's directly a result of MongoDB using memory mapped file IO (http://en.wikipedia.org/wiki/Memory-mapped_file http://en.wikipedia.org/wiki/Memory-mapped_file) which gets better performance, but on a 32-bit system you're constrained to the amount of memory addressable by a 32-bit process. So rather than do somewhat hacky (and complex) code they opted to be forward looking and just leave the limitation in place. Thankfully, with a 64-bit OS the upper limit goes up to 256 terabytes.