These issues with Hadoop and HDFS in particular are pretty well documented even by people in the Hadoop project. There was also a bunch of blog posts posted at

These issues with Hadoop and HDFS in particular are pretty well documented even by people in the Hadoop project. There was also a bunch of blog posts posted at Yahoo shortly after Cutting's departure that looked at a bunch of other issues with the IO subsystem. Much of this stuff has been heavily refactored, particularly with Hadoop 2.0, so the problems are at least much smaller than they used to be. Early Hadoop was not exactly a masterful work in terms of the code & algos. What was great about it was the community that was built around it.