Hi,we just came across a very serious problem with Hadoop (and any other nio intense Java-application) and kernel 2.6.27.
Short story:Increase epoll maximum_instances (/proc/sys/fs/epoll/max_user_instances) to prevent "Too many open files" errors regardless your ulimit -n settings.
Long story: http://pero.blogs.aprilmayjune.org/2009/01/22/hadoop-and-linux-kernel-2627-epoll-limits/I just wanted to drop this note since it took us 2 days to figure it out... :(
Regards Peter
