NioNettySuiteHammerTest is failing with an error "java.net.SocketException: Too many open files". Right now ulimit -n is set to 4096. I'll ask infra to increase the ulimit, but what should the value be? 10000?
https://builds.apache.org/view/S-Z/view/ZooKeeper/job/PreCommit-ZOOKEEPER-Build/2357/
