short ttl and servermmirroring

[Kevin Darcy]

Barry Margolin 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.

There's no doubt it's intentional -- RFC 1996 (NOTIFY) suggests the practice,
although stops short of actually recommending it. The author is Vixie, of
BIND fame...


- Kevin