short ttl and servermmirroring

hilgart at my-deja.com hilgart at my-deja.com
Thu Feb 17 22:31:18 UTC 2000


At the suggestion of Jim Reid, I looked at the code and found that BIND
does indeed intentionally put a delay in sending out NOTIFY from
anywhere between 5 seconds to 15 minutes, using a random value.  The
delay is roughly proportional to the number of zones you have.

For us this is unfortunate as this is an ideal high-availability
mechanism.  It looks simple enough to re-write the code, and I may do
so.  Once we sign up for a support contract with the ISC, I will suggest
that some more switches be offered around this cool NOTIFY feature.

I'm surprised there hasn't been more request for this.  If you want to
switch the IP of your Web server in seconds (or at least within
minutes), you need 1) a short TTL on its record and 2) all authoritative
servers to have that new IP ASAP .?  This thread is focussed on 2) .
Isn't that how Distribued Director and Resonate Global Dispatch work?

Or am I missing something?
-john
BASF Corporation
In article <FAzq4.50$M31.3128 at burlma1-snr2>,
  Barry Margolin <barmar at bbnplanet.com> wrote:
> In article <88citf$36h$1 at nnrp1.deja.com>,  <hilgart at netscape.net>
wrote:
> >I have a related question.  I'm really eager to use the BIND 8 NOTIFY
> >FEATURE but in my tests between to BIND 8.2.2 p 5 servers, it's
taking
> >longer than I'd like - anywhere from 30 seconds to a few minutes.
That
> >is, the primary server is waiting that long before initiating a
NOTIFY
> >to the secondary when a domain has changed.  The secondary picks up
the
> >new zone instantly once it has been NOTIFY'd.
> >
> >I was hoping for a 1- or 2-second value for this feature to kick in.
> >These timings are key to enable rapid failover to back-up servers.
> >
> >What are other people's experiences?  What might be slowing this
down?
>
> I think this is intentional.  It waits a random amount of time to keep
from
> flooding a slave server with NOTIFY messages all at once.
>
> The purpose of NOTIFY isn't to achieve instant propagation, just to be
much
> better than waiting for the Refresh period.
>
> --
> 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.
>
>


Sent via Deja.com http://www.deja.com/
Before you buy.



More information about the bind-users mailing list