Maintained by: NLnet Labs

[Unbound-users] Problems with 100% CPU load of unbound

Sebastian Nickel - Hetzner Online AG
Thu Jul 22 14:50:46 CEST 2010


Hello,
we use unbound in a loadbalancer configuration. We noticed that
sometimes the unbound process uses 100% of CPU even when it does not
receive any DNS requests. It uses this 100% cpu load till we restart the
process. After restarting all is ok again.

We don't know why this happens. We used unbound from debian-testing and
a self compiled version, too. The issue happened in both installations. 

Does anybody have any information about this issue?

Currently used versions:

unbound:
--------
self compiled, configure options: "--without-pthreads
--without-solaris-threads"
Version 1.4.4
linked libs: event 3.9, ldns 1.4.0, OpenSSL 0.9.8o 01 Jun 2010
linked modules: validator iterator

OS:
---
Debian Lenny
Kernel: 2.6.26-2-amd64


unbound.conf
------------
server:
	verbosity: 0
	num-threads: 2
	interface: 0.0.0.0
	interface-automatic: yes
	outgoing-range: 450
	msg-cache-size: 333m
        msg-cache-slabs: 4
	rrset-cache-size: 666m
	rrset-cache-slabs: 4
	infra-cache-slabs: 4
	access-control: 0.0.0.0/0 allow
	chroot: ""
	key-cache-slabs: 4


Thanks...