Bind9 Crazy-high CPU on Linux

Matthew Schlosser mschlosser at
Thu Jan 18 17:37:53 UTC 2007

Thank you for all the references and help.

I upgraded to 9.4rc1 with the following results:

Massive jump in memory usage (about double).  The named process now shows a
memory footprint of close to 900MB where before 500MB would kill it.

CPU stays between 20-25% and spikes to 30-35% during a cleaning interval
which lasts only a minute or two.

Previously with 9.3.2, rndc status showed upwards of 2,000 or more recursive
clients.  Now it shows only less than 500 at any given time and the output
format has changed:

recursive clients: 463/3900/4000

The server has been up a little over 36 hours.

I also noted three new items in the named.stats file.  "Duplicate" and
"dropped" are new values.  Does anyone know how to fit them in to the
greater scheme?  For example recursion can be subtracted from a combined
total of success, referral, nxrrset, nxdomain and failure to generate a
percentage.  Where do the new values fit?

success 30428464
referral 2099872
nxrrset 6270659
nxdomain 16121686
recursion 29924813
failure 8892309
duplicate 1101621
dropped 159814


> -----Original Message-----
> From: bind-users-bounce at 
> [mailto:bind-users-bounce at] On Behalf Of Stefan Puiu
> Sent: Tuesday, January 16, 2007 8:13 AM
> To: Schlosser, Matt D.
> Cc: bind-users at
> Subject: Re: Bind9 Crazy-high CPU on Linux
> Hi,
> On 1/15/07, Schlosser, Matt D. <mschlosser at> wrote:
> > The machines run between 800 and 1,000 queries/second for both
> > authoritative and recursive zones.  After 12-24 hours, the CPU will
> > spike to 100% and sit there while the machine times out any more
> > queries.  The only resolution is to restart bind.
> I haven't personally experienced this, but I've seen it reported quite
> a few times on this list. IIRC, it's been reported that the cache
> cleaning can be quite heavy sometimes, so you might want to adjust the
> cleaning interval.
> Also, recompiling BIND with internal malloc support was reported to
> help (this requires editing a header file IIRC). That part seems to be
> detailed here:
> thread/thread/c830e65e2247c630/bfe3178894e98351?lnk=gst&q=jinm
> ei+internal+malloc&rnum=1#bfe3178894e98351
> No idea why running on Windows would make a difference.
> Look in the archives, I believe it's been quite well covered.
> Stefan.

More information about the bind-users mailing list