Interesting case happened out dev HBase cluster overnight. (We're running HBase 0.94.15 from CDH 4.6.0)
A region server took a StackOverflow error, it looks like during during a minor compaction. The region server is trying to shut down with a Fatal, but is now hung during shutdown. The particularly troublesome thing is that the RS is alive enough to keep zookeeper happy. So, the regions arent moving off, but our apps cant get to them because the RS is mostly dead. I put some of the details on pastebin. JStack -> http://pastebin.com/hnLtaG54 Outfile -> http://pastebin.com/5F1UcGjg Logfile -> http://pastebin.com/TBL1YSZM
