Allen Wittenauer of LinkedIn will give a talk the week of march 12 on Hadoop Ops -he's presenting this at Hadoop Summit EU the following week.
Allen's cluster is 600+ nodes, running LinkedIn's graph work, and is very unusual in that
-it's CPU intensive rather than IO bound
-Allen is prepared to talk about it.
Allen is notorious in the Hadoop community as the voice of operations -the loud voice- and is a committer on the hadoop projects. Prior to joining LinkedIn, he managed Yahoo!'s Hadoop clusters -and has the dirt on everybody in the Hadoop development space.
Follow him on twitter at @_a__w_