Re: [Pdns-users] Recursor: Different answers for the same query
On Wed, Jan 26, 2011 at 10:32:19AM +0100, Christian Kuehn wrote: Hi, Hey there, any idea why the pdns-recursor 3.3 gives different answers to the same query?? Looks like a bug?? The recursor now scales over CPUs and cores by default and maintains a cache per 'thread', hence it _might_ give different answers from cache on occasion. - http://doc.powerdns.com/changelog.html#changelog-recursor-3-2 Multithreading, allowing near linear scaling to multiple CPUs or cores. Configured using 'threads=' (many commits). This also deprecates the '--fork' option. This version of the PowerDNS Recursor contains a rather novel form of lock-free multithreading, a situation that comes close to the old '--fork' trick, but allows the Recursor to fully utilize multiple CPUs, while delivering unified statistics and operational control. In effect, this delivers the best of both worlds: near linear scaling, with almost no administrative overhead. Compared to 'regular multithreading', whereby threads cooperate more closely, more memory is used, since each thread maintains its own DNS cache. However, given the economics, and the relatively limited total amount of memory needed for high performance, this price is well worth it. So it's not a bug, but by design. In normal DNS operations you should not get different responses, however your example seems to be one of those edge cases where you do. I'm getting a REFUSED from both pns.dtag.de and secondary000.dtag.net for that query btw. Note that you can also fire up the recursor with the trace=yes option in order to find out where exactly the recursion process goes haywire, however be advised that this causes a _lot_ of logging output. Stefan -- The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair. - Douglas Adams, Mostly Harmless ___ Pdns-users mailing list Pdns-users@mailman.powerdns.com http://mailman.powerdns.com/mailman/listinfo/pdns-users
Re: [Pdns-users] Recursor: Different answers for the same query
On Wed, Jan 26, 2011 at 10:32:19AM +0100, Christian Kuehn wrote: any idea why the pdns-recursor 3.3 gives different answers to the same query?? Hello!! ;-) You probably run with threads=2, and one of the threads has had problems resolving cecilmen.se, and the other hasn't. 3.3.1 which will be released soon tries a bit harder to resolve domains when timeouts happen, which should reduce this from happening. But at the root, there is no bug needed to explain what you are seeing. Bert tks@tks:~$ dig ns cecilmen.se ; DiG 9.7.0-P1 ns cecilmen.se ;; global options: +cmd ;; Got answer: ;; -HEADER- opcode: QUERY, status: NOERROR, id: 24828 ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 2 ;; QUESTION SECTION: ;cecilmen.se. IN NS ;; ANSWER SECTION: cecilmen.se. 86126 IN NS pns.dtag.de. cecilmen.se. 86126 IN NS secondary000.dtag.net. ;; ADDITIONAL SECTION: pns.dtag.de. 86373 IN A 194.25.0.125 secondary000.dtag.net.84792 IN A 195.244.245.7 ;; Query time: 0 msec ;; SERVER: 212.1.60.5#53(212.1.60.5) ;; WHEN: Wed Jan 26 10:28:49 2011 ;; MSG SIZE rcvd: 121 tks@tks:~$ dig ns cecilmen.se ; DiG 9.7.0-P1 ns cecilmen.se ;; global options: +cmd ;; Got answer: ;; -HEADER- opcode: QUERY, status: SERVFAIL, id: 30008 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;cecilmen.se. IN NS ;; Query time: 0 msec ;; SERVER: 212.1.60.5#53(212.1.60.5) ;; WHEN: Wed Jan 26 10:28:49 2011 ;; MSG SIZE rcvd: 29 Looks like a bug?? Cheers Christian -- Christian Kühn (Technical Consultant) == MCS MOORBEK COMPUTER SYSTEME GmbH Essener Bogen 17 - 22419 Hamburg - Germany Tel +49 (0)40 53773 0 - Fax: +49 (0)40 53773 200 E-Mail: christian.ku...@mcs.de Web: http://www.mcs.de Eingetragen im Handelsregister Hamburg B62933 Geschäftsführer: Kai Brandes Eckard Kabel GPG 8B52 41A1 4B8F 4DE7 9064 2073 6168 137A 3DDA 0F36 == ___ Pdns-users mailing list Pdns-users@mailman.powerdns.com http://mailman.powerdns.com/mailman/listinfo/pdns-users ___ Pdns-users mailing list Pdns-users@mailman.powerdns.com http://mailman.powerdns.com/mailman/listinfo/pdns-users
Re: [Pdns-users] Recursor: Different answers for the same query
They don't share the same cache? What's the reasoning behind that? On Jan 26, 2011, at 1:55 AM, bert hubert wrote: On Wed, Jan 26, 2011 at 10:32:19AM +0100, Christian Kuehn wrote: any idea why the pdns-recursor 3.3 gives different answers to the same query?? Hello!! ;-) You probably run with threads=2, and one of the threads has had problems resolving cecilmen.se, and the other hasn't. 3.3.1 which will be released soon tries a bit harder to resolve domains when timeouts happen, which should reduce this from happening. But at the root, there is no bug needed to explain what you are seeing. Bert tks@tks:~$ dig ns cecilmen.se ; DiG 9.7.0-P1 ns cecilmen.se ;; global options: +cmd ;; Got answer: ;; -HEADER- opcode: QUERY, status: NOERROR, id: 24828 ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 2 ;; QUESTION SECTION: ;cecilmen.se.IN NS ;; ANSWER SECTION: cecilmen.se. 86126 IN NS pns.dtag.de. cecilmen.se. 86126 IN NS secondary000.dtag.net. ;; ADDITIONAL SECTION: pns.dtag.de. 86373 IN A 194.25.0.125 secondary000.dtag.net. 84792 IN A 195.244.245.7 ;; Query time: 0 msec ;; SERVER: 212.1.60.5#53(212.1.60.5) ;; WHEN: Wed Jan 26 10:28:49 2011 ;; MSG SIZE rcvd: 121 tks@tks:~$ dig ns cecilmen.se ; DiG 9.7.0-P1 ns cecilmen.se ;; global options: +cmd ;; Got answer: ;; -HEADER- opcode: QUERY, status: SERVFAIL, id: 30008 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;cecilmen.se.IN NS ;; Query time: 0 msec ;; SERVER: 212.1.60.5#53(212.1.60.5) ;; WHEN: Wed Jan 26 10:28:49 2011 ;; MSG SIZE rcvd: 29 Looks like a bug?? Cheers Christian -- Christian Kühn (Technical Consultant) == MCS MOORBEK COMPUTER SYSTEME GmbH Essener Bogen 17 - 22419 Hamburg - Germany Tel +49 (0)40 53773 0 - Fax: +49 (0)40 53773 200 E-Mail: christian.ku...@mcs.de Web: http://www.mcs.de Eingetragen im Handelsregister Hamburg B62933 Geschäftsführer: Kai Brandes Eckard Kabel GPG 8B52 41A1 4B8F 4DE7 9064 2073 6168 137A 3DDA 0F36 == ___ Pdns-users mailing list Pdns-users@mailman.powerdns.com http://mailman.powerdns.com/mailman/listinfo/pdns-users ___ Pdns-users mailing list Pdns-users@mailman.powerdns.com http://mailman.powerdns.com/mailman/listinfo/pdns-users ___ Pdns-users mailing list Pdns-users@mailman.powerdns.com http://mailman.powerdns.com/mailman/listinfo/pdns-users
