Hi, I'm running unbound with 4 separate threads and I notice that sometimes the same query returns ok and sometimes returns error. I understood that with 4 threads each one have a separate cache. Is this correct ? So maybe one cache has the data and other couldn't get it. Normally the query below returns ok: ---------------------------------------------- # dig @wks11.rjo www.sun.com.br ; <<>> DiG 9.3.4-P1 <<>> @wks11.rjo www.sun.com.br ; (1 server found) ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9503 ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 4, ADDITIONAL: 4 ;; QUESTION SECTION: ;www.sun.com.br. IN A ;; ANSWER SECTION: www.sun.com.br. 37931 IN CNAME br.sun.com. br.sun.com. 37931 IN A 72.5.124.12 ;; AUTHORITY SECTION: sun.com. 39455 IN NS ns1.sun.com. sun.com. 39455 IN NS ns2.sun.com. sun.com. 39455 IN NS ns7.sun.com. sun.com. 39455 IN NS ns8.sun.com. ;; ADDITIONAL SECTION: ns1.sun.com. 36656 IN A 192.18.128.11 ns2.sun.com. 84888 IN A 192.18.99.5 ns7.sun.com. 36656 IN A 192.18.43.15 ns8.sun.com. 36656 IN A 192.18.43.12 ;; Query time: 0 msec ;; SERVER: 200.255.125.211#53(200.255.125.211) ;; WHEN: Thu Jan 15 10:13:01 2009 ;; MSG SIZE rcvd: 208 ---------------------------------------------- But sometimes returns: ---------------------------------------------- # dig @wks11.rjo www.sun.com.br ; <<>> DiG 9.3.4-P1 <<>> @wks11.rjo www.sun.com.br ; (1 server found) ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 21333 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;www.sun.com.br. IN A ;; Query time: 0 msec ;; SERVER: 200.255.125.211#53(200.255.125.211) ;; WHEN: Thu Jan 15 10:12:59 2009 ;; MSG SIZE rcvd: 32 ---------------------------------------------- What is happening here ? When I run with 1 thread I never had these symptom. The hardware: Intel Xeon with 8 processors, 5G memory CentOS release 5.2 unbound 1.2.0 compile options: --without-pthreads --without-solaris-threads unbound.conf: num-threads: 4 outgoing-range: 700 num-queries-per-thread: 700 outgoing-num-tcp: 10 incoming-num-tcp: 10 rrset-cache-size: 1000m msg-cache-size: 100m rrset-cache-slabs: 8 msg-cache-slabs: 8 infra-cache-slabs: 8 key-cache-slabs: 8 The server have an average load of 10000 qry/min so its quite free. Thanks, Roberto