I noticed very strange but consistent performance behavior from Google Public DNS 8.8.8.8
. Even-though a DNS record was cached, the response time was in the range of 20-30ms
, which seems high. When I switched over to OpenDNS, cached response times dived down to 1ms
. Needless to say just made the switch on all the servers to OpenDNS. Can anybody explain this poor performance behavior from Google Public DNS?
Here is the output from dig for each test case:
Google Public DNS
Uncached (389ms)
➜ ~ dig @8.8.8.8 commando.io
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.6 <<>> @8.8.8.8 commando.io
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 655
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;commando.io. IN A
;; ANSWER SECTION:
commando.io. 300 IN A 192.241.225.51
;; Query time: 389 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Sun Sep 22 12:08:37 2013
;; MSG SIZE rcvd: 45
Cached (24ms)
➜ ~ dig @8.8.8.8 commando.io
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.6 <<>> @8.8.8.8 commando.io
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 55425
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;commando.io. IN A
;; ANSWER SECTION:
commando.io. 295 IN A 192.241.225.51
;; Query time: 24 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Sun Sep 22 12:08:42 2013
;; MSG SIZE rcvd: 45
OpenDNS
Uncached (46ms)
➜ ~ dig commando.io
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.6 <<>> commando.io
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 49578
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;commando.io. IN A
;; ANSWER SECTION:
commando.io. 300 IN A 192.241.225.51
;; Query time: 46 msec
;; SERVER: 208.67.222.222#53(208.67.222.222)
;; WHEN: Sun Sep 22 12:09:43 2013
;; MSG SIZE rcvd: 45
Cached (1ms)
➜ ~ dig commando.io
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.6 <<>> commando.io
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42532
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;commando.io. IN A
;; ANSWER SECTION:
commando.io. 273 IN A 192.241.225.51
;; Query time: 1 msec
;; SERVER: 208.67.222.222#53(208.67.222.222)
;; WHEN: Sun Sep 22 12:10:10 2013
;; MSG SIZE rcvd: 45