On Thu, Nov 14, 2013 at 10:05 AM, J. Ryan Earl <oss@jryanearl.us> wrote:
* Cassandra 2.0.2 has a lot of improvements, consider upgrading.  We noticed improved heap usage compared to 2.0.2


And especially if you're using Level Compaction / LCS :

"Wrong tracking of minLevel in Leveled Compaction Strategy causing serious performance problems"

tl;dr - don't upgrade to 2.0.2 in production.