Hi again, I have checked this again today.
Send & receive buffers are both 1MB, the Server has 8 CPUs and during startup BIND is reporting this: found 8 CPUs, using 8 worker threads using 7 UDP listeners per interface using up to 32768 sockets We only have about 1.500 queries per second on this server. CPU(30%) and memory(50%) usage also is not an issue here. Now Oracle support is saying that the buffer sizes are fine and we need to "speed up the application" to read the data faster from the receive buffer and this prevent package drops. Do you think that is a reasonable statement in this environment ? What would be the best way to "speed up the application" ? Just increase the worker threads ? Regards Marc On 06/28/17 15:31, Marc Richter wrote: > Hi Ben, > > thanks for the answer. > > Yeah, I think you are right. I see a lot of udpInOverflows on the system, > which suggest that the receive buffer is too small indeed. > > Is there any kind of recommendation or best-practice advice what the > buffers should ideally be set to on Solaris ? > I did search the ISC Knowledge Base, but didn't find any useful advice. > > Regards > arc > > On 06/28/17 14:37, Ben Croswell wrote: >> Have you checked deeper at the OS level? I have seen on Linux DNS servers >> silent drops of queries on very busy servers that were exhausting UDP >> receive buffers. >> >> On Jun 28, 2017 10:26 AM, "Marc Richter" <marc.rich...@de.verizon.com >> <mailto:marc.rich...@de.verizon.com>> wrote: >> >> Hi, >> >> we have a setup here consisting of a recursive DNS server and two >> monitoring servers. The monitoring servers sent a test query to the DNS >> server once every two minutes to check if it is answering properly. >> >> We now have the problems that these test queries are timing out from time >> to time, (correctly) resulting in alarms in our monitoring system. >> >> I have checked this now and noticed that each time we see that alarm, the >> query sent by the monitoring server is not being answered at all. >> To debug that I ran tcpdump on both the monitoring server and the >> recursive >> DNS server. I see the query being sent out on the monitoring server and I >> also see the query being received on the DNS server, however there is no >> response sent to this query at all. >> Looking at the query log, which I enabled temporarily, the query is also >> not logged there so it looks like BIND is ignoring that query somewhere, >> although it is properly received by the IP stack of the server. >> >> Do you have any suggestions how to debug this further, to hopefully find >> out where these queries are stuck/dropped/ignored, as I have run out of >> ideas ? >> >> The environment is: >> BIND 9.9.9-P5 (Extended Support Version) <id:1ab232a> >> running on SunOS sun4v 5.11 11.3 >> >> >> Thanks ! >> Marc >> _______________________________________________ >> Please visit >> https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.isc.org_mailman_listinfo_bind-2Dusers&d=DwICAg&c=udBTRvFvXC5Dhqg7UHpJlPps3mZ3LRxpb6__0PomBTQ&r=wDgZv-d1RrBMzWr_7pSF_09ZAXIr59EgoXQU4ctOHMk&m=b8p_t6atDvFHu2tWe4Jgw_EvLufZakMUJL0w06aA3V0&s=bXYnQq1IzLGZG6xbey81qsaTVpqiLVlwxazV8CXVP_A&e= >> >> >> <https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.isc.org_mailman_listinfo_bind-2Dusers&d=DwMFaQ&c=udBTRvFvXC5Dhqg7UHpJlPps3mZ3LRxpb6__0PomBTQ&r=wDgZv-d1RrBMzWr_7pSF_09ZAXIr59EgoXQU4ctOHMk&m=t6jk-SZ5v_kNlupaNbpfob7Dm6Iddy_gUndDBwWnkmc&s=Ko40xVILMIdx3tQ9ElkdPqboTH8RpH1ZKJ4ZXcGp9NM&e=> >> to unsubscribe from this list >> >> bind-users mailing list >> bind-users@lists.isc.org <mailto:bind-users@lists.isc.org> >> >> https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.isc.org_mailman_listinfo_bind-2Dusers&d=DwICAg&c=udBTRvFvXC5Dhqg7UHpJlPps3mZ3LRxpb6__0PomBTQ&r=wDgZv-d1RrBMzWr_7pSF_09ZAXIr59EgoXQU4ctOHMk&m=b8p_t6atDvFHu2tWe4Jgw_EvLufZakMUJL0w06aA3V0&s=bXYnQq1IzLGZG6xbey81qsaTVpqiLVlwxazV8CXVP_A&e= >> >> >> <https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.isc.org_mailman_listinfo_bind-2Dusers&d=DwMFaQ&c=udBTRvFvXC5Dhqg7UHpJlPps3mZ3LRxpb6__0PomBTQ&r=wDgZv-d1RrBMzWr_7pSF_09ZAXIr59EgoXQU4ctOHMk&m=t6jk-SZ5v_kNlupaNbpfob7Dm6Iddy_gUndDBwWnkmc&s=Ko40xVILMIdx3tQ9ElkdPqboTH8RpH1ZKJ4ZXcGp9NM&e=> >> >> > -- Marc Richter Engr III Cslt-Ntwk Eng&Ops Sebrathweg 20 44149 Dortmund Germany O +49 231 972 1293 F +49 231 972 2587 E marc.rich...@de.verizon.com _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users