DHCP failover - disk full, can not commit to lease file

[Doug Barton]

I could make a pretty good argument that "My disk is full and I cannot 
write leases" would be something that should trigger failover.

Doug


On 05/27/2013 03:56 PM, Steven Carr wrote:
> No, your disk is full (and you risk more issues than just DHCP
> problems), DHCPD needs to be able to write the lease information to
> disk, without that that it will not function. The DHCP failover
> protocol does not take into account the resources on the local system
> when assigning DHCP leases, it assumes your resources are adequate
> enough for the job.
>
>
>
> On 27 May 2013 19:53, Louis Lau <Louis_Lau at nechk.nec.com.hk> wrote:
>> Dear all,
>>
>> I have two DHCP servers configured as failover peer and the router relay the
>> DHCP/Bootp request to both server. When the system works normaly, a DHCP
>> discover from client will be broadcast to both server and the observed
>> behavour is that both server will offer an DHCP OFFER to the same client,
>> The primary DHCP server shall reply an IP-A managed by the Primary, and the
>> Secondary shall reply an IP-B that is managed by the secondary. Assume the
>> client select IP-A and send an DHCP Request for IP-A to both server.
>>
>> However recently, primary server disk is full, and in the log there are a
>> lot of
>>
>> ommit_leases: unable to commit: No space left on device
>>
>> We observed that the DHCP does not failover to the secondary in this case,
>> and the primary will still response to DHCPDISCOVER and provide a DHCP
>> Offer.  And in this case, we observed that most client does not try the DHCP
>> offer from secondary but most of them choose the IP assigned from the
>> Primary DHCP server.
>>
>> Is this behaviour normal?
>>
>> Are there any configuration that can make the server fail to secondary DHCP
>> server for similar case or let the client try the other DHCP OFFER when the
>> first DHCP IP does not have a ACK?
>>
>> Thanks for your help on this matter.
>>
>>
>> Louis Lau