- http://stackoverflow.com/questions/15359271/low-memory-consumption-with-mongodb
- http://www.kchodorow.com/blog/2012/05/10/thursday-5-diagnosing-high-readahead/
- http://serverfault.com/questions/408100/mongodb-and-datasets-that-dont-fit-in-ram-no-matter-how-hard-you-shove
- http://markmail.org/message/utuxcatjdgxwe72z
- http://docs.mongodb.org/manual/administration/production-notes/#readahead
- http://linux.die.net/man/8/blockdev