Hi John
On 22/03/2012 14:16, "John Baldwin" <j...@freebsd.org> wrote: >On Thursday, March 22, 2012 6:03:21 am Traiano Welcome wrote: >> Hi List >> >> I've been seeing the following in the messages log of my freebsd syslog >> server for quite some time now: >> >> --- >> Mar 20 12:19:12 syslog2 syslog-ng[35313]: I/O error occurred while >> writing; fd='12', error='No buffer space available (55)' >> Mar 20 12:19:12 syslog2 syslog-ng[35313]: Connection broken; >> time_reopen='60' >> Mar 20 12:19:12 syslog2 syslog-ng[35313]: I/O error occurred while >> writing; fd='13', error='No buffer space available (55)' >> Mar 20 12:19:12 syslog2 syslog-ng[35313]: Connection broken; >> time_reopen='60' >> --- >> >> These happen at a frequency of about 7 per minute on average. See >>attached >> trend graphs for an idea of the volume of traffic we're doing, as well >>as >> the memory and cpu utilisation trends on this server during this period. >> As can be seen from the graphs, load does not seem to be the issue. >> Occasionally during the week, the system freezes and requires a reboot, >>I >> think it's related to the above message, though I'm not sure. >> >> My question is: What does this error mean, and how can I resolve it? >> >> I have tried to frame this as an operating system kernel resource issue, >> and experimented with increasing the freebsd kernel sysctls for UDP >> performance: > >It means that the network driver has "filled" up with packets. Are you >using >igb(4)? We have to crank the number of descriptors assigned to igb to >the max >to workaround this at work (we get DNS timeouts during a simple boot >otherwise). hw.igb.maxtxd is the tunable you would set. The max value >you >can set it to is 4096. Thanks for the clue. It seems igb is indeed being used. However, I not that when I try to list this tunable, I don't get anything: --- [root@syslog2]# sysctl -a | grep igb [root@syslog2]# --- --- [root@syslog2 /boot]# sysctl hw.igb.maxtxd=4000 sysctl: unknown oid 'hw.igb.maxtxd' --- Is this due to the way igb is compiled into the kernel, or am I tuning in the wrong place :-) > >-- >John Baldwin _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
