Need to improve named performance

Florian Weimer fw at
Mon Nov 12 06:56:17 UTC 2012

* Ed LaFrance:

> Thanks for chiming in. Named is PID 8349 in my case. Here's a snippet
> of the output from strace:

> [pid  8351] send(3, "<30>Nov 11 13:07:25 named[8349]:"..., 107,
> MSG_NOSIGNAL) = 107 <0.015232>

> [pid  8353] send(3, "<30>Nov 11 13:07:25 named[8349]:"..., 103,

> [pid  8353] <... send resumed> )        = 103 <0.015034>

This look like syslog logging is the culprit, each syslog message
takes 15ms to complete.

There could be several causes: syslogd is logging synchronously to
disk (doing an fsync after each message), something else in the system
is producing an extremely large number of messages (syslogd is
single-threaded), or there is a request loop where writing out the
syslog message for each reverse DNS request requires itself a reverse
DNS lookup.

You should also check if named is expected to log this many messages
in the first place.  You can pass "-s 200" to strace to see more of
the logging message, so this should help to identify what's going on.

I don't think this has got anything to do with the particular BIND
version you use.

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