Bind CPU ussage issue

Peter Dambier peter at
Tue Jun 27 19:02:47 UTC 2006

Jeff Lightner wrote:
> I saw this on my Linux system when I had configured Bind ACLs to use the
> internal NIC instead of the external NIC even though most queries were
> to come through the external.  Changing to the external NIC resolved it.
> -----Original Message-----
> From: bind-users-bounce at [mailto:bind-users-bounce at] On
> Behalf Of Mike O'Hara
> Sent: Tuesday, June 27, 2006 1:11 PM
> To: comp-protocols-dns-bind at
> Subject: Bind CPU ussage issue
> I am having a helleva time managing Bind on my server.
> Server Specs are
> Dual Xeon 2.66 GHZ
> 1 Gb ram
> Windows 2003 Server
> ISC Bind 9.2.2
> Now Bind will regularly spike up to 100% CPU usage and stay there
> untill the named service is restarted. then it will work its way back
> up there again after a non descript period of time.
> Is there a configuration glitch that is causing it to eat CPU cycles
> like they are going out of style? or will upgrading to the latest
> release solve my issues?

I used to run Bind 9.2 and Bind 9.3 on

cat /proc/cpuinfo

cpu family      : 4
model           : 0
bogomips        : 18.94

cat /proc/meminfo

         total:    used:    free:  shared: buffers:  cached:
Mem:  14737408 13434880  1302528  3059712  1413120  6639616
Swap: 134176768  2469888 131706880
MemTotal:     14392 kB
MemFree:       1272 kB
MemShared:     2988 kB
Buffers:       1380 kB
Cached:        6484 kB
SwapTotal:   131032 kB
SwapFree:    128620 kB

Linux version 2.2.19 (root at fm)
  (gcc version 2.95.3 20010315 (SuSE))
  #15 Sun Nov 24 22:34:59 CET 2002

I had similar experiences.

Now I am running BIND 9.4.0a6


cat /proc/cpuinfo

cpu             : 486
model           : 486 DX-25/33
vendor_id       : GenuineIntel
bogomips        : 18.94

cat /proc/meminfo

         total:    used:    free:  shared: buffers:  cached:
Mem:  14540800 12181504  2359296  2285568  1343488  4046848
Swap: 133885952 12746752 121139200
MemTotal:     14200 kB
MemFree:       2304 kB
MemShared:     2232 kB
Buffers:       1312 kB
Cached:        3952 kB
SwapTotal:   130748 kB
SwapFree:    118300 kB

Linux version 2.0.36 (root at lomi)
  (gcc version  {Unifix 2.0}
  #13 Die Jun 20 18:59:19 CED 2006

It is the same kind of hardware. I downgraded back to linux 2.0
The problem seems to be the ethernet driver on linux 2.2 and 2.4
I tried 2.6 on a different hardware (windows + CoLinux), same problem.

I guess it is about duplex full or duplex half.

I have do have fewer problems on a switch than on a hub.

The problem is not only with Bind but with other programmes too, like
telnet and ssh, even ftp.

The problem is not Bind.

Nevertheless there are moments when Bind takes a nap:

When bind gets an updated zone file from a master (authoritative only)
or when it does a garbadge collection on memory (cache only).

Having only 16 MB really and 128 MB virtual, that is not much of a problem
on my small machine.

I am not running a big company, but only my small home network with a
workstation and three general purpose servers, all linux.

The machine running Bind is doing other work too. Im doing a lot of
DNS queries on both machines. I dont see any more cpu 100% on the
linux 2.0 but on the 2.2 it is unchanged.

OT: djbdns shows the same behavior. That is why I am shure the problem
is not Bind. :)

Peter and Karin

Peter and Karin Dambier
Cesidian Root - Radice Cesidiana
Graeffstrasse 14
D-64646 Heppenheim
+49(6252)671-788 (Telekom)
+49(179)108-3978 (O2 Genion)
+49(6252)750-308 (VoIP:
mail: peter at
mail: peter at

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