Differential updates in Multi GB zone files.

[Mark.Andrews at nominum.com]

	See IXFR, Incremental zone transfer.

	Mark
> 
> Hi,
> 	How does one manage zone updates of when having multiple DNS
> servers which hold a multi-GB zone file.
> 
> 	Are there any extensions or scripts out there to do this? How do
> the root servers move the zone file around? using zone x-fer? Or do you
> gzip it and ftp it over?
> 
> 	Maybe I am reinventing the wheel but it would be neat that rather
> than just transfer a huge file from one master to n slaves which are in
> geographically disperse locations/networks, to actually add an extension
> the the zone x-fer protocol and make it a bit more intelligent.
> 
> 	When updating a zone file, it would be good if the server would
> keep the differences (insertions/deletions) between the zone file of the
> previous serial number and the current one by doing a comparision of
> serial numbers or keep updates in a journal file.
> 
> 	When a slave is sent a notify or a slave does a AXFR, the slave
> would would get the changes not the whole zone file. BIND could keep a
> hash of the last zone it has in memory when updates are done, slave and
> masters could exchange hashes to ensure that they both hold the same data.
> If the hash fails, then it does a old fashioned AXFR.
> 
> 	Maybe my idea is not too polished but I am sure someone can come
> up with something along these lines to solve this problem.
> 
> A solution which I am not sure if will work....
> 
> 	I see that BIND 9.0 has some database extensions to host the zone
> files in an SQL back end. The sql backend could be used to do the zone
> replication, which is neat, good bye zone updates, here come real time DNS
> changes. How well would an SQL back end handle huge loads compared to the
> current bind? Can someone teach me a bit on this?
> 
> Regards,
> Maren.
> 
> 
> 
--
Mark Andrews, Nominum Inc.
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at nominum.com