Cade Metz at the Register discusses Colossus (GFS2) and Caffeine. http://www.theregister.co.uk/2010/09/09/google_caffeine_explained/ They permit more timely index updates than MapReduce. A paper is to be presented at the USENIX Symposium on Operating Systems Design and Implementation (OSDI). http://www.usenix.org/events/osdi10/

http://blogoscoped.com/forum/171693.html
http://blogoscoped.com/archive/2009-08-11-n28.html

http://www.picotech.com/applications/colossus.html
http://en.wikipedia.org/wiki/Colossus:_The_Forbin_Project
:)