max-cache-size (was: no subject)
Evan_Hunt at isc.org
Tue May 27 20:15:05 UTC 2008
> Hmmm... how to reconcile this with the previous reports on bind-users
> of memory usage mushrooming out of control in 9.5.0 alpha/beta releases?
> Have those been satisfactorily resolved now?
That issue wasn't related to cache performance. It's a bug that would
show up on authoritative servers handling a very large number of zones,
especially if they also use large ACLs--the people who've reported it had
tens to hundreds of thousands of zones, and ACLs with thousands of elements.
The problem was that zone ACLs (allow-transfer, allow-notify, allow-query,
etc) were being copied into each zone rather than loaded into memory once
and then referenced by the zones that use them. That adds up after a while.
Regrettably, the problem was noticed too late in the test cycle for a fix
to be included in 9.5.0 (which we expect to be public in a few more days).
A patch will be included in the KNOWN-DEFECTS file (read: "not tested to
ISC's official satisfaction; use at your own risk--but I, the author,
personally believe it to be solid"). After more thorough testing it'll
be incorporated into 9.5.1.
Caching resolvers shouldn't be affected at all. Authoritative servers
with a smaller number of zones will be affected but it won't bother them
much. People running authoritative servers with huge numbers of zones
who are brave enough to use a point-zero release in the first place are
hopefully brave enough to risk the KNOWN-DEFECTS patch. :)
Cache performance should be improved regardless.
Evan Hunt -- evan_hunt at isc.org
Internet Systems Consortium, Inc.
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