NOTIFY

Barry Margolin barmar at bbnplanet.com
Wed Sep 29 22:13:53 UTC 1999


In article <7stto5$p32 at journal.concentric.net>,
Bill DeStein <bill at ffnet.com> wrote:
>I'm considering an unconventional application for DNS
>which will require frequent updates to the zone data of
>my primary server(s).
>
>I'd like to use caching to help with scalability, but my
>application cannot tolerate incoherence between cached
>data and primary zone data.
>
>I believe I can use slave servers, and use NOTIFY
>to synchronize master/slave data.  But I'm afraid of the
>flash effect caused by these zone transfers as my network
>grows.

How big are your domains?  I just did a zone transfer of a domain with
almost 5,000 records between servers in Cambridge, MA and Washington, DC,
and it took about a second.  For a domain with 27,000 records it took about
5 seconds.

If your domain really is big enough for network load to be an issue, can
you break it up into subdomains?  Then there will be less to transfer at a
time.

>It seems that what I need are caching-only servers
>that receive NOTIFY messages from the master and
>simply invalidate (delete) their cache entries without
>initiating a zone transfer.
>
>Can BIND 8.x do this?

There's nothing built in to do it.

>Seems like an easy change for me to make.  True?

I suppose so, I haven't checked the code.

-- 
Barry Margolin, barmar at bbnplanet.com
GTE Internetworking, Powered by BBN, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.


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