[nsd-users] NSD 4.1.9 release

[Stuart Henderson]

On 2016/03/15 12:40, Anand Buddhdev wrote:
> Thanks for this! We were affected by this issue as well, because some
> of our servers were still using the DB mode.
> 
> However, I have changed our internal SPEC file to build NSD with:
> 
> - --with-dbfile=""
> 
> so that all our NSD instances will use plain text zone files by
> default, and simply not use the DB mode.
> 
> FYI for all NSD users. Wouter added this "nodb" mode at our request,
> and it works really well for us. An NSD server that has only slave
> zones will XFR them all in at startup. Periodically (default every
> 1h), it will flush the zones to plain text files on disk, so that when
> NSD is restarted, it can read the zones back in. If 1 hour seems too
> long to wait before writing out changed zones to disk, one can adjust
> the value in nsd.conf.
> 
> In the event of a restart with unflushed zones, NSD will just read an
> older copy of the zone from disk, and then immediately XFR a new copy
> in. If you wish, you can also run "nsd-control write" before
> restarting NSD, so that it restarts with the freshest copy of zones.
> In my opinion though, all this isn't really necessary, because
> restarts are rare, and if the odd zone here or there hadn't been
> flushed to disk, it will be updated to the latest copy within moments
> of starting NSD.
> 
> I can highly recommend the "nodb" mode by setting "database:" to "" in
> nsd.conf, or making this the default at compile time with the
> configure option I mentioned above.

We're using this as the OpenBSD default too (after I ran into some
problems with the dbfiles before, which I suspect may possibly have
been related to lack of cache coherency between mmap and file access
on OpenBSD).

I was initially uncertain if switching to "nodb" mode might
introduce performance problems during restarts but it has been
absolutely fine.