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<p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thanks for your tip about syslog! My failover configuration was
taking about 3 minutes to synchronize after a restart, now it takes only a few
seconds!!! <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div>
<p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Denis
Laventure</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Service
des technologies de l'information</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Université
du Québec à Chicoutimi</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>418-545-5011
poste 2380</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>http://www.uqac.ca<o:p></o:p></span></p>
</div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'>
<p class=MsoNormal><b><span lang=FR style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>De :</span></b><span
lang=FR style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
dhcp-users-bounce@isc.org [mailto:dhcp-users-bounce@isc.org] <b>De la part de</b>
Brad Dameron<br>
<b>Envoyé :</b> 17 octobre 2008 04:22<br>
<b>À :</b> dhcp-users@isc.org<br>
<b>Objet :</b> RE: Guidelines for Sever dimensioning<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<div id=idOWAReplyText48423>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:black'>We are a large ISP and have several hardware configurations. I can
tell you the following configuration and what it is doing in production right
now.</span><span lang=EN-US><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Pentium
4 3Ghz, 1 GB RAM, 80Gb SATA-I hard drive.</span><span lang=EN-US><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>It
is currently handling a little over 25,000 clients with a 24 hour
lease time. This is a mixed OS type of client.</span><span lang=EN-US><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>In
our lab we did many tests and with a AMD X2 6000+ with 4GB of DDR2 800 and
a Gigabyte i-RAM ramdisk with 4GB on it we were able to handle upwards of
350k clients. This was using Nominum's dhcperf test too with a 24 hour lease
time. 200k customers was achievable with a 250GB SATA-II Seagate enterprise
drive.</span><span lang=EN-US><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>We
also had modified the source code slightly to adjust a hash setting. You can find
that in the list email. Just search for my name.</span><span lang=EN-US><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>The
AMD processor was ultimately the best for handling DHCP. This is due to how it
handles memory. </span><span lang=EN-US><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Also
one huge performance enhancement on our linux servers was due to the dhcp
logging itself. If you use syslogd you need to look at putting a hypen in front
of the path/filename like:</span><span lang=EN-US><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>#
DHCP message into seperate file<br>
local6.*
-/var/log/dhcpd.log</span><span lang=EN-US><o:p></o:p></span></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Or
if you don't log to a specific file and log to messages:<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>*.info;mail.none;news.none;authpriv.none;cron.none;
-/var/log/messages<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>If
you use syslog-ng then in the conf change:<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>options
{<br>
sync (0);<br>
<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>TO:<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>options
{<br>
sync (20);<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>What
this does is to only write 20 lines to the log at a time. Instead of writing
every line individually. This saves on a lot of disk activity and heavily
increases DHCP performance.<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'><br>
<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Brad
Dameron<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Clearw're<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Senior
Systems Engineer<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p>
</div>
</div>
<div>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<div class=MsoNormal align=center style='text-align:center'><span lang=EN-US>
<hr size=2 width="100%" align=center>
</span></div>
<p class=MsoNormal style='margin-bottom:12.0pt'><b><span lang=EN-US
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
dhcp-users-bounce@isc.org on behalf of T Manikandan-Q3926C<br>
<b>Sent:</b> Thu 10/16/2008 11:24 PM<br>
<b>To:</b> dhcp-users@isc.org<br>
<b>Subject:</b> Guidelines for Sever dimensioning</span><span lang=EN-US><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Hi,</span><span
lang=EN-US><o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Can
anybody help me in dimensioning the DHCP server?</span><span lang=EN-US><o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>I
Have X number of clients to be supported by the server. How will I obtain the
CPU, RAM and Hard disk calculations?</span><span lang=EN-US><o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Say
for X number of clients each client takes 4 transactions to get the IP from the
DHCP server, considering each packet of size 576 octects, takes 576*4= 2304
octects</span><span lang=EN-US><o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>For
X clients considering 100% client attached during busy hour it will be ( 2304 *
X ) octects, or (2304 * X *8/3600) bytes per second, which is the bandwidth
but, </span><span lang=EN-US><o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>How
should the dimension be for the CPU, RAM and Harddisk. ( Taking account for OS
, especially for RHEL),</span><span lang=EN-US><o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Regards</span><span
lang=EN-US><o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Mani</span><span
lang=EN-US><o:p></o:p></span></p>
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