UDP packet loss

[Paul Vixie]

> >> ... It seems to me that the problem is UDP packet loss.
> >
> >> RedHat Linux ES release 4, 2.6.9-34.ELsmp kernel, dual Opteron system 
> >> with 6GB ram, no local zones, just resolver/cache. bind-9.3.2-2_EL4
> > 
> > A quick question: did you enable threads?
> 
> As far as I know, RedHat's packages are compiled with threads enabled. 
> This server is quite busy, about 4MBit of DNS traffic for hours...

that is not the modern definition of "busy".  a dual opteron system running
9.3.2 with threads enabled can handle a lot more (a LOT more) than 4MBit/sec
of query load.  otoh you really need to build it yourself, to be sure you
know the conditions under which you are measuring; and you really need to try
9.4.0-alpha (see ftp://ftp.isc.org/isc/bind9/, 9.4.0a6 is today's best) with
threads enabled, with and without the internal memory allocator, before you'll
know what your hardware and kernel are actually capable of.
-- 
Paul Vixie