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: DHCP pair messed up, second one only running cant get primary up. (Simon Hobson) 2. Re: DHCP pair messed up, second one only running cant get primary up. (Rob Morin) 3. RE: DHCP pair messed up, second one only running cant get primary up. (Rob Morin) ---------------------------------------------------------------------- Message: 1 Date: Fri, 13 Jan 2017 20:30:59 +0000 From: Simon Hobson <dh...@thehobsons.co.uk> To: Users of ISC DHCP <dhcp-users@lists.isc.org> Subject: Re: DHCP pair messed up, second one only running cant get primary up. Message-ID: <70be0d13-efa4-4c30-9275-d44a0d2cf...@thehobsons.co.uk> Content-Type: text/plain; charset=iso-8859-1 Rob Morin <rmo...@datavalet.com> wrote: > Also the dhcpd.leases files grow too big for the /ramdisk, so we are each 10 > mins catting /dev/null into /ramdisk/dhcpd.lease! file to save space. I can't help with the other problems, but pray you don't have to stop the DHCP server at any time before it's re-written the compacted leases file ! Losing the leases file is "bad" in a big way. I can't help with the specific problem, but I would suggest that if you lengthen the lease time (by a considerable amount) it will dramatically reduce the rate of growth of the leases file. With a lease length of 20 minutes, you'll have a renewal every 10 minutes (roughly) - so that's 6 lease updates to the leases file per hour ! For example, if you were to increase the lease time to (say) 4 hours, then your leases file would contain one record per lease (in practical terms, every address in your pools) plus one update for roughly 1/2 the active clients. So your lease file size will change from total of IP ranges + 6x number of active clients, to total of IP ranges plus 1/2 the active clients. Is there a reason for having such short leases ? It's quite short, longer leases bring much stability and much more leeway in dealing with DHCPO service issues ! Also, for consideration, you can have more than 2 servers in failover - but only 2 per pool. So it's possible to have (say) 3 servers sharing the load as A+B, B+C, and C+A. More complexity, but more scope for server failure without losing DHCP service - and more load sharing. Of course, you can also just split pools across an even number of servers as A+B, C+D, etc. ------------------------------ Message: 2 Date: Fri, 13 Jan 2017 21:39:01 -0500 From: Rob Morin <rmo...@datavalet.com> To: Simon Hobson <dh...@thehobsons.co.uk>, Users of ISC DHCP <dhcp-users@lists.isc.org> Subject: Re: DHCP pair messed up, second one only running cant get primary up. Message-ID: <hagtsfbg05u10i9g8sutthd2.1484361541...@email.android.com> Content-Type: text/plain; charset="utf-8" Sorry I had a typo in my email we cat /dev/null into dhcp. leases~ file not the active file? Sent from Samsung Mobile <div>-------- Original message --------</div><div>From: Simon Hobson <dh...@thehobsons.co.uk> </div><div>Date:01-13-2017 3:30 PM (GMT-05:00) </div><div>To: Users of ISC DHCP <dhcp-users@lists.isc.org> </div><div>Subject: Re: DHCP pair messed up, second one only running cant get primary up. </div><div> </div>Rob Morin <rmo...@datavalet.com> wrote: > Also the dhcpd.leases files grow too big for the /ramdisk, so we are each 10 > mins catting /dev/null into /ramdisk/dhcpd.lease! file to save space. I can't help with the other problems, but pray you don't have to stop the DHCP server at any time before it's re-written the compacted leases file ! Losing the leases file is "bad" in a big way. I can't help with the specific problem, but I would suggest that if you lengthen the lease time (by a considerable amount) it will dramatically reduce the rate of growth of the leases file. With a lease length of 20 minutes, you'll have a renewal every 10 minutes (roughly) - so that's 6 lease updates to the leases file per hour ! For example, if you were to increase the lease time to (say) 4 hours, then your leases file would contain one record per lease (in practical terms, every address in your pools) plus one update for roughly 1/2 the active clients. So your lease file size will change from total of IP ranges + 6x number of active clients, to total of IP ranges plus 1/2 the active clients. Is there a reason for having such short leases ? It's quite short, longer leases bring much stability and much more leeway in dealing with DHCPO service issues ! Also, for consideration, you can have more than 2 servers in failover - but only 2 per pool. So it's possible to have (say) 3 servers sharing the load as A+B, B+C, and C+A. More complexity, but more scope for server failure without losing DHCP service - and more load sharing. Of course, you can also just split pools across an even number of servers as A+B, C+D, etc. _______________________________________________ dhcp-users mailing list dhcp-users@lists.isc.org https://lists.isc.org/mailman/listinfo/dhcp-users -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://lists.isc.org/pipermail/dhcp-users/attachments/20170113/04464a5a/attachment-0001.html> ------------------------------ Message: 3 Date: Sat, 14 Jan 2017 07:23:22 +0000 From: Rob Morin <rmo...@datavalet.com> To: Users of ISC DHCP <dhcp-users@lists.isc.org> Subject: RE: DHCP pair messed up, second one only running cant get primary up. Message-ID: <sn2pr01mb1983ac12484ffb8aa74e9f3dca...@sn2pr01mb1983.prod.exchangelabs.com> Content-Type: text/plain; charset="iso-8859-1" Our lease time is governed by our client, which is huge. That cannot be changed. :) Rob Morin Gestionnaire des syst?mes | Senior System administrator T 514 385-4448 #174 DATAVALET.COM 5275, chemin Queen-Mary, Montr?al (Qu?bec) H3W 1Y3 Canada CE COURRIEL AINSI QUE CES DOCUMENTS JOINTS peuvent contenir des renseignements confidentiels et privil?gi?s. Si vous n'?tes pas le destinataire d?sign?, veuillez nous en informer imm?diatement et effacer toute copie. Merci. THIS EMAIL AND THE DOCUMENTS ATTACHED may contain privileged or confidential information. If the reader of this message is not the intended recipient, please notify the sender immediately and delete the original message. Thank you. -----Original Message----- From: dhcp-users [mailto:dhcp-users-boun...@lists.isc.org] On Behalf Of Simon Hobson Sent: Friday, January 13, 2017 3:31 PM To: Users of ISC DHCP <dhcp-users@lists.isc.org> Subject: Re: DHCP pair messed up, second one only running cant get primary up. Rob Morin <rmo...@datavalet.com> wrote: > Also the dhcpd.leases files grow too big for the /ramdisk, so we are each 10 > mins catting /dev/null into /ramdisk/dhcpd.lease! file to save space. I can't help with the other problems, but pray you don't have to stop the DHCP server at any time before it's re-written the compacted leases file ! Losing the leases file is "bad" in a big way. I can't help with the specific problem, but I would suggest that if you lengthen the lease time (by a considerable amount) it will dramatically reduce the rate of growth of the leases file. With a lease length of 20 minutes, you'll have a renewal every 10 minutes (roughly) - so that's 6 lease updates to the leases file per hour ! For example, if you were to increase the lease time to (say) 4 hours, then your leases file would contain one record per lease (in practical terms, every address in your pools) plus one update for roughly 1/2 the active clients. So your lease file size will change from total of IP ranges + 6x number of active clients, to total of IP ranges plus 1/2 the active clients. Is there a reason for having such short leases ? It's quite short, longer leases bring much stability and much more leeway in dealing with DHCPO service issues ! Also, for consideration, you can have more than 2 servers in failover - but only 2 per pool. So it's possible to have (say) 3 servers sharing the load as A+B, B+C, and C+A. More complexity, but more scope for server failure without losing DHCP service - and more load sharing. Of course, you can also just split pools across an even number of servers as A+B, C+D, etc. _______________________________________________ dhcp-users mailing list dhcp-users@lists.isc.org https://lists.isc.org/mailman/listinfo/dhcp-users ------------------------------ Subject: Digest Footer _______________________________________________ dhcp-users mailing list dhcp-users@lists.isc.org https://lists.isc.org/mailman/listinfo/dhcp-users ------------------------------ End of dhcp-users Digest, Vol 99, Issue 6 *****************************************