Send dhcp-users mailing list submissions to
dhcp-users@lists.isc.org
To subscribe or unsubscribe via the World Wide Web, visit
https://lists.isc.org/mailman/listinfo/dhcp-users
or, via email, send a message with subject or body 'help' to
dhcp-users-requ...@lists.isc.org
You can reach the person managing the list at
dhcp-users-ow...@lists.isc.org
When replying, please edit your Subject line so it is more specific
than "Re: Contents of dhcp-users digest..."
Today's Topics:
1. Re: [EXTERNAL] Re: extremely slow DHCPD startup time (perl-list)
2. Re: extremely slow DHCPD startup time (Kenneth Porter)
----------------------------------------------------------------------
Message: 1
Date: Fri, 5 Aug 2022 09:45:07 -0400 (EDT)
From: perl-list <perl-l...@network1.net>
To: Users of ISC DHCP <dhcp-users@lists.isc.org>
Subject: Re: [EXTERNAL] Re: extremely slow DHCPD startup time
Message-ID:
<1472584730.3031281.1659707107543.javamail.zim...@network1.net>
Content-Type: text/plain; charset=utf-8
This wouldn't happen to be on a virtual would it?
In my somewhat limited experience (only a couple high traffic DHCP servers in
virtuals - many on single SSD storage systems), I/O is a problem for DHCP
servers installed in virtual infrastructure (no matter what sort of storage you
have on the back end). A single CPU - multi core Xeon 1U system with a single
SSD and 16GB RAM will run circles around virtuals for ISC DHCP in the I/O
department. No idea why.
----- Original Message -----
> From: "Shane Merritt" <smerr...@ua.edu>
> To: "Users of ISC DHCP" <dhcp-users@lists.isc.org>
> Sent: Thursday, August 4, 2022 4:18:04 PM
> Subject: Re: [EXTERNAL] Re: extremely slow DHCPD startup time
> The server disks are already SSD. The total max available lease space
> according
> to dhcpd-pools is 283,751. I did a restart on one of the pair earlier and the
> time was about 10 minutes, but activity is low at the moment since fall
> semester hasn?t begun.
> Shane Merritt
> Office of Information Technology
> The University of Alabama
> smerr...@ua.edu
> From: dhcp-users <dhcp-users-boun...@lists.isc.org> on behalf of Sten Carlsen
> <st...@s-carlsen.dk>
> Date: Thursday, August 4, 2022 at 2:54 PM
> To: Users of ISC DHCP <dhcp-users@lists.isc.org>
> Subject: [EXTERNAL] Re: extremely slow DHCPD startup time
>> On 4 Aug 2022, at 21.05, Greg Sloop < [ mailto:gr...@sloop.net |
>> gr...@sloop.net
>> ] > < [ mailto:gr...@sloop.net | gr...@sloop.net ] > wrote:
>> I'm sure others will have some useful suggestions - but I do know that
>> improving
>> disk I/O can seriously improve performance.
>> I'm not sure if that will improve restart/start/reload times.
>> It would be pretty easy to test though, say swapping for an SSD/Nvme.
>> (Or if you like living dangerously, putting the disk in RAM.)
>> On Thu, Aug 4, 2022 at 12:02 PM Shane Merritt < [ mailto:smerr...@ua.edu |
>> smerr...@ua.edu ] > wrote:
>>> I have a failover pair of DHCP servers running 4.4.2-P1 that handle a DHCP
>>> for a
>>> very large wireless network (>75k devices active at any time). The leases
>>> file
>>> on these boxes is around 200 megabytes. The problem I am having is when I
>>> need
>>> to make a change and restart, DHCPD takes over 25 minutes to start giving
>>> out
>>> addresses. I assume this is due to the large lease file. I see that there
>>> are
>>> tons of leases in the file that are ?binding state free? that in some cases
>>> are
>>> months old. Are there any suggestions to improve this situation?
> AFAIK the server will fill its internal tables with every possible lease, most
> of them empty or marked free. I could be wrong about this.
> So the question is how large your net blocks are?
> If you e.g. have a /8 address space, that would amount to the server having to
> populate 2^24 (16 mill) entries in its internal table and do what ever
> processing etc it does for each entry. This may take time.
>>> Shane Merritt
>>> Office of Information Technology
>>> The University of Alabama
>>> [ mailto:smerr...@ua.edu | smerr...@ua.edu ]
>>> --
>>> ISC funds the development of this software with paid support subscriptions.
>>> Contact us at [
>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.isc.org%2Fcontact%2F&data=05%7C01%7Csmerritt%40ua.edu%7Cd99158278556462fa2f908da76532816%7C2a00728ef0d040b4a4e8ce433f3fbca7%7C0%7C0%7C637952396772922435%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=9iElG3QLIZLtUu%2FEirPM5%2FaBw73HUohsnqapHOwRe2k%3D&reserved=0
>>> |
>>> https://www.isc.org/contact/ ] for more information.
>>> dhcp-users mailing list
>>> [ mailto:dhcp-users@lists.isc.org | dhcp-users@lists.isc.org ]
>>> [
>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.isc.org%2Fmailman%2Flistinfo%2Fdhcp-users&data=05%7C01%7Csmerritt%40ua.edu%7Cd99158278556462fa2f908da76532816%7C2a00728ef0d040b4a4e8ce433f3fbca7%7C0%7C0%7C637952396772922435%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=QrJKq7HH3dsRdL3dQ6rFKHVuk9xQuxMBRbd0r3Ze3vg%3D&reserved=0
>>> | https://lists.isc.org/mailman/listinfo/dhcp-users ]
>> --
>> ISC funds the development of this software with paid support subscriptions.
>> Contact us at [
>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.isc.org%2Fcontact%2F&data=05%7C01%7Csmerritt%40ua.edu%7Cd99158278556462fa2f908da76532816%7C2a00728ef0d040b4a4e8ce433f3fbca7%7C0%7C0%7C637952396772922435%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=9iElG3QLIZLtUu%2FEirPM5%2FaBw73HUohsnqapHOwRe2k%3D&reserved=0
>> |
>> https://www.isc.org/contact/ ] for more information.
>> dhcp-users mailing list
>> [ mailto:dhcp-users@lists.isc.org | dhcp-users@lists.isc.org ]
>> https://lists.isc.org/mailman/listinfo/dhcp-users
> --
> ISC funds the development of this software with paid support subscriptions.
> Contact us at https://www.isc.org/contact/ for more information.
> dhcp-users mailing list
> dhcp-users@lists.isc.org
> https://lists.isc.org/mailman/listinfo/dhcp-users
------------------------------
Message: 2
Date: Fri, 05 Aug 2022 09:55:15 -0700
From: Kenneth Porter <sh...@sewingwitch.com>
To: Users of ISC DHCP <dhcp-users@lists.isc.org>
Subject: Re: extremely slow DHCPD startup time
Message-ID: <61F9937FEEEAEB65706AFFFD@[192.168.69.69]>
Content-Type: text/plain; charset=us-ascii; format=flowed
--On Thursday, August 04, 2022 8:01 PM +0000 Shane Merritt
<smerr...@ua.edu> wrote:
> The leases file on these boxes is around 200 megabytes.
I'd suggest trying Kea, the ISC DHCP server that's undergoing active
development. There's a tool to migrate the old configuration to the new
JSON format. Alas, there's no tool to migrate the lease file. That sounds
like a big obstacle for migrating big sites or testing the new software
against a big existing deployment database.
------------------------------
Subject: Digest Footer
_______________________________________________
ISC funds the development of this software with paid support subscriptions.
Contact us at https://www.isc.org/contact/ for more information.
dhcp-users mailing list
dhcp-users@lists.isc.org
https://lists.isc.org/mailman/listinfo/dhcp-users
------------------------------
End of dhcp-users Digest, Vol 166, Issue 3
******************************************
