<HTML dir=ltr><HEAD>
<META http-equiv=Content-Type content="text/html; charset=unicode">
<META content="MSHTML 6.00.6000.16735" name=GENERATOR>
<STYLE>
<!--
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman";}
a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{color:purple;
text-decoration:underline;}
span.EmailStyle17
{
font-family:Arial;
color:windowtext;}
div.Section1
{page:Section1;}
-->
</STYLE>
</HEAD>
<BODY lang=EN-US vLink=purple link=blue>
<DIV id=idOWAReplyText48423 dir=ltr>
<DIV dir=ltr><FONT face=Arial color=#000000 size=2>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.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>Pentium 4 3Ghz, 1 GB RAM, 80Gb SATA-I hard drive.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>It is currently handling a little over 25,000 clients with a 24 hour lease time. This is a mixed OS type of client.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>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.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>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.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>The AMD processor was ultimately the best for handling DHCP. This is due to how it handles memory. </FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>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:</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2># DHCP message into seperate file<BR>local6.* -/var/log/dhcpd.log</FONT></DIV><FONT face=Arial size=2></FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2>
<DIV dir=ltr> </DIV>
<DIV dir=ltr>Or if you don't log to a specific file and log to messages:</DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr>*.info;mail.none;news.none;authpriv.none;cron.none; -/var/log/messages</DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr>If you use syslog-ng then in the conf change:</DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr>options {<BR> sync (0);<BR> </DIV>
<DIV dir=ltr>TO:</DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr>options {<BR> sync (20);</DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr>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.</DIV>
<DIV dir=ltr><BR> </DIV>
<DIV dir=ltr>Brad Dameron</DIV>
<DIV dir=ltr>Clearw're</DIV>
<DIV dir=ltr>Senior Systems Engineer</DIV></FONT>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV></DIV>
<DIV dir=ltr><BR>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> 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<BR></FONT><BR></DIV>
<DIV>
<DIV class=Section1>
<P class=MsoNormal><FONT face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Hi,</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Can anybody help me in dimensioning the DHCP server?</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">I Have X number of clients to be supported by the server. How will I obtain the CPU, RAM and Hard disk calculations?</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">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></FONT></P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">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></FONT></P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">How should the dimension be for the CPU, RAM and Harddisk. ( Taking account for OS , especially for RHEL),</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Regards</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Mani</SPAN></FONT></P></DIV></DIV></BODY></HTML>