Runping Qi wrote:
If you may have turned on ipv6 on your hadoop cluster, it may cause severe
performance hit!
Suggested Workaround:
Either set -Djava.net.preferIPv4Stack=true for the child process option,
which forces Java to use IPv4
instead, or you disable IPv6 entirely in the system. The proper fix is to
allow IPv6 traffic from localhost to localhost.
For more information, see the Sun documentation:
http://java.sun.com/j2se/1.4.2/docs/guide/net/ipv6_guide/#ipv6-networking
Seems to me, disabling IPv6 is a legit action on any network that thinks
addresses should fit in 32 bits. Linux desktop perf with IPv6 turned on
(including firefox performance) is worse, hence turning it off is a well
known action, one of the simple ways to speed up your box
http://ubuntuforums.org/showthread.php?t=6841
my own modprobe.d/aliases files hint that the test for ipv6 live is the
line:
ip a | grep inet6
