DHCP Queue

Blake Hudson blake at ispn.net
Thu Feb 12 19:39:58 UTC 2009

And if you can't run the newest version of DHCP... If your SAS
controller has a write cache, enable it. The bottleneck in your DHCP
server is likely disk. If you can remove that, you could probably serve
a few thousand lease per second with your CPU.


-------- Original Message  --------
Subject: Re: DHCP Queue
From: Brad Dameron <Brad.Dameron at clearwire.com>
To: Users of ISC DHCP <dhcp-users at lists.isc.org>
Date: Thursday, February 12, 2009 11:26:07 AM
> You can increase the lease per second substantually by going with
> 3.1.x and using the hash adjustment I have posted on this list before.
> I have gotten it into the 400 lps range with this. And I also tested
> with DHCPperf tool as well as some other in house generated perl
> scripts. Search the archive for my name.
> Brad Dameron
> Clearw're
> Engineering
> ------------------------------------------------------------------------
> *From:* dhcp-users-bounces at lists.isc.org on behalf of T MANIKANDAN-PKXR74
> *Sent:* Wed 2/4/2009 9:01 AM
> *To:* Users of ISC DHCP
> *Subject:* RE: DHCP Queue
> Hello can any one help to my query mentioned below.
> Regards
> Mani
> ------------------------------------------------------------------------
> *From:* dhcp-users-bounces at lists.isc.org
> [mailto:dhcp-users-bounces at lists.isc.org] *On Behalf Of *T
> *Sent:* Tuesday, February 03, 2009 7:30 PM
> *To:* dhcp-users at lists.isc.org
> *Subject:* DHCP Queue
> Hi,
>    We have a Network element AAA where it sends 250 clients per second
> to aquire a Lease from ISC DHCP server. and I have seen that a 4 way
> quad core AMD opteron processor/ SAS I/O drive with RHEL 5 and ISC
> DHCP 3.0.5 can handle upto 125 lease per second ( Result achieved from
> Nominum DHCPperf tool).
>    With total 135000 clients in my network it takes around 18 min to
> complete the lease ( Time taken= (135000/125)/60 = 18 Minutes), When
> my AAA network element which is used for authentication and
> other purpose finishes the job in approx 8 Minutes, while my DHCP
> server take 18 Minutes to complete the Job.
>    Say at the end of 3 seconds, DHCP server gets a hit of 750
> (250+250+250) Discover request while only 375 (125+125+125) is being
> allocated an ip address and balance 375 will be in a queue similarly..... 
>   at the end of 500 seconds, my DHCP server would have got aprox
> 135000 discover request and it has processed only approx 65000 request
> and balance 75000 will be pending in the queue.
> My queries
> How long the client request will remain in queue
> what will be the maximum attempt the client will make to obtain the lease.
> What will be the state of clients which are there in queue.
> Is there any other Best solution in which my DHCP server can handle
> all 250 clients at a second
> Can i have 2 DHCP server in active active state handling different
> scopes so that all 250 request are handled and there is no queue if so
> how the lease file will be maintained.
>   Please help me understanding how the DHCP server handles this situation
> Regards
> Mani
> ------------------------------------------------------------------------
> _______________________________________________
> dhcp-users mailing list
> dhcp-users at lists.isc.org
> https://lists.isc.org/mailman/listinfo/dhcp-users

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