Migration from one failover pair to two pairs; strategy, questions

[Nick Urbanik]

Dear Folks,

Thank you Glenn.

On 21/01/08 00:21 +1100, Glenn Satchell wrote:
>>1. Can I create two global failover peer statements in /etc/dhcpd.conf
>>    like this (for step 3. above, on primary-a):
>>failover peer "seta" {
>>         primary;
>>         address primary-a;
>>         port 520;
>>         peer address secondary-a;
>>         peer port 520;
>>         max-response-delay 60;
>>         max-unacked-updates 10;
>>         mclt 3600;
>>         split 128;
>>         load balance max seconds 3;
>>}
>>failover peer "setb" {
>>         primary;
>>         address primary-a;
>>         port 520;
>>         peer address secondary-b;
>>         peer port 520;
>>         max-response-delay 60;
>>         max-unacked-updates 10;
>>         mclt 3600;
>>         split 128;
>>         load balance max seconds 3;
>>}

Do you know if this is true?

>>2. Can anyone suggest a better/simpler migration strategy?  Most
>>    important aim is to avoid any outage.
>
>I think this will work, but there are three re-starts involved.
>
>Another approach would be create the configuration you want in
>dhcpd.conf for seta and setb, copy the dhcpd.leases files from the
>corresponding primary hosts and start it up. There will be some time
>spent as it discards all the leases for ip addresses outside the
>subnets defined, but after that will operate normally.

Of course, you're right, that would work nicely; the leases are not
changed, only the configuration.  There's no need to transfer the
leases again!

>With the scale of your client base I can't estimate how long that
>will take. Maybe you should set up some test servers and try it out?

Yes, certainly I will try it out in a test environment.
-- 
Nick Urbanik http://nicku.org 808-71011 nick.urbanik at optusnet.com.au
GPG: 7FFA CDC7 5A77 0558 DC7A 790A 16DF EC5B BB9D 2C24  ID: BB9D2C24
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