On Thu, Mar 24, 2011 at 12:07:06PM -0700, Steve Jenkins wrote:
> On Thu, Mar 24, 2011 at 10:34 AM, Victor Duchovni
> <victor.ducho...@morganstanley.com> wrote:
> > If all you changed was adding a local DNS cache, unless your previous
> > cache was >100ms away, you'll not see much change.
>
> Actually, after doing some tests with dig on our colo provider's DNS
> servers we noticed that they were taking an avg of 200+ msec for a
> reply, and sometimes over 400! We had no idea it was that bad. Again,
> we're not sure if this change will have any impact on Postfix's
> delivery times yet, but it's fun to try and optimize. :)
This is not unreasonable for a cache "miss", but if this is also the
latency for a cache "hit", you have a good incentive to avoid this
DNS cache.
I hope you measured whether a second lookup for the same RRset showed
equally long latencies.
--
Viktor.
