DHCP/UDP performance tuning..

Cory Meyer cory.meyer at gmail.com
Tue Mar 27 20:52:21 UTC 2007

Thanks everyone..   Looks like my first step will be to do the obvious and
increase lease times to 8/12 hrs  along with set the minimum lease time for
unregistered users to 10 minutes.   That alone should significantly decrease
the amount of requests hitting the server.  Next steps would be to try and
reduce the dependency on fsync().  I do have a script on another machine
that parses the dhcpd.leases over NFS every 5 minutes..  My guess is that
also has some sort of effect.
Thanks again for tall the help..
-- Cory

On 3/27/07, David W. Hankins <David_Hankins at isc.org> wrote:
> On Tue, Mar 27, 2007 at 11:31:17AM -0500, Cory Meyer wrote:
> > Does anyone have any suggestions on performance tuning a DHCP server?
> http://marc.info/?l=dhcp-users&m=115334003807766&w=2
> One-line summary:  dhcpd performance is bound to fsync(), which is
> called once for every REQUEST/ACK pair.  Other stuff on your system
> that also calls fsync() (such as syslog) should probably be shot.
> In some future release (I'm told the sky will be blue), we hope
> to queue ACKs into a list...fsync() once and then transmit them
> all.  This would multiply our scaling point on this bottleneck
> by several hundred most likely.
> --
> ISC Training!  http://www.isc.org/training/  training at isc.org
> Washington DC area, April 16-20 2007.  DNS & BIND, DDNS & DHCP.
> --
> David W. Hankins        "If you don't do it right the first time,
> Software Engineer               you'll just have to do it again."
> Internet Systems Consortium, Inc.       -- Jack T. Hankins

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