Query timeouts on FreeBSD 7 over network

Igor V. Ruzanov igorr at canmos.ru
Tue Aug 5 11:37:54 UTC 2008

> I've tried with the ULE scheduler and 4BSD and tried with and with
> out PREEMPTION turned on. Nothing makes a difference.
First of all you could try to connect only two machines via cross-over 
cable, no any switches between the machines, no any VLANs and so on. 
FreeBSD-7.0 works better with ULE-scheduler and kernel should be 
preemtive (options PREEMPTION in kernel config).
- what is your kernel config?

> I'm pretty sure this is related to the OS or the em driver in some way, because if I disable all ICMP rate limiting and run an extended ping from the local firewall, I experience a very low amount of random packet loss in no pattern, unlike if you have the ICMP rate limiting enabled.
Once again it would be better if you do analyze the traffic going throuth 
the em-interface excluding your DNS testing data. Try to get the network 
with no any walking packets but dnsperf traffic and no any upinks and/or 

> Also, are there any documented recommendations for sysctl values for FreeBSD when running BIND for optimal performance?
- What options did you provide to configure script during BIND building?
One of necessary options should be --enable-threads if you build BIND 
under FreeBSD 7.0.

! CANMOS ISP Network                        !
! Best regards                              !
! Igor V. Ruzanov, network operational staff!
! e-Mail: igorr at canmos.ru                   !

More information about the freebsd-stable mailing list