O Canada! > Canadian > TekSavvy > Google DNS versus ours

reply to mlord

Re: Google DNS versus ours

k, well we are changing these. This is still surprising though since we were using bind...which is pretty much de facto standard DNS server out there.

Yes, very surprising to us when it happens, too.
If there was a good way to let TSI know about it (specific site lookup failing), we'd probably do it. But it's just easier to run my own DNS (bind) than to monkey around with rebooting my router, changing cables, disconnecting/reconnecting the modem etc.. just to report a DNS issue.

Cheers

namebench gives me 25-26msec average lookups for the same server as in post #1 above, versus 45-46msec for 8.8.8.8.

Cheers

reply to TSI Gabe
These, in the vast majority of cases relate to who is caching what.

I looked at one of these complaints earlier, and it turns out, google had a later version of a DNS record.

A breakdown is like this:

Time 0:
 
A record is www.example.org 10.1.1.1  TTL 3600 (3600, one hour, usually much higher (like a day) for crappy dns providers)
 
TSI DNS: no copy
Google DNS: no copy
 
Time 1:
 
A Google user checks out the site
 
TSI DNS: no copy
Google DNS: 10.1.1.1, 3600  (will be cached for 3600 more seconds)
 
Time 1800:
 
A TekSavvy user checks out the site
 
TSI DNS: 10.1.1.1, 3600
Google DNS: 10.1.1.1, 1800
 
Time 3500:
 
Site decides they wish to update their A record to 10.1.1.2
 
TSI DNS: 10.1.1.1, 1900
Google DNS: 10.1.1.1, 100
 
Time 3600:
 
Googles cache expires
 
TSI DNS: 10.1.1.1, 1800
Google DNS: no copy
 
Time 3601:
 
Google user requests the site again
 
TSI DNS: 10.1.1.1, 1700
Google DNS: 10.1.1.2, 3600
 

$ dig teksavvy.com @8.8.8.8 && dig teksavvy.com @206.248.142.222
 
; <<>> DiG 9.8.1-P1 <<>> teksavvy.com @8.8.8.8
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27201
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
 
;; QUESTION SECTION:
;teksavvy.com. IN A
 
;; ANSWER SECTION:
teksavvy.com. 30 IN A 206.248.155.70
 
;; Query time: 35 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Thu Oct 11 10:25:57 2012
;; MSG SIZE  rcvd: 46
 
; <<>> DiG 9.8.1-P1 <<>> teksavvy.com @206.248.142.222
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39145
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
 
;; QUESTION SECTION:
;teksavvy.com. IN A
 
;; ANSWER SECTION:
teksavvy.com. 1800 IN A 206.248.155.70
 
;; Query time: 10 msec
;; SERVER: 206.248.142.222#53(206.248.142.222)
;; WHEN: Thu Oct 11 10:25:57 2012
;; MSG SIZE  rcvd: 46
 

Might be interesting to automate a cache purge if requested from MyTools.

You could have the client submit problematic DNS record from the website, compare your DNS server's copy to google & opendns. If your serial is less than theirs, flush the cache entry.

You could report that the entry is fine, or out of date and flushed.

EDIT: all the lookups, and comparisons are done on the webserver, when authenticated, so it wouldn't affect actual DNS performance, and shouldn't raise security issues. Just the cache purge for that record happens on the name server see: rndc flushname

reply to derekm
In the breakdown you show.. the times listed are how much longer it will remain cached based on when it was last refreshed.. in other words, in your example, it's not because google updates more often then ours, that's generally set by the DNS record holder.. it's like you say.. depends on when it was last updated..

Like I mentioned, each time I hear somebody say our dns this or that.. I kind of scratch my head because I haven't seen a case where it was clearly our dns server at fault...

this new upgrade though is pretty sweet.. nice to see that it's significantly faster.
--
Marc - CEO/TekSavvy

Agreed - it's how DNS should work.

You could build the facility to report out of date zones - and have it automatically QC'd. Would it ever get used? That's a different question!

And yes, great job on the new servers!

@TSIMarc:
An even easier solution, set the max-cache-ttl and max-ncache-ttl :

»www.zytrax.com/books/dns/ch7/hkp···ache-ttl

You can auto-expire your cache settings every 10 minutes - 1 hour.

yeah but that doesn't lead to better performance.. you want records that are accurate to stay cached so their response is fast.. having to go query the auth dns server where the records are hosted is the part that takes the longest...

sometimes this is why larger dns servers may perform better since they have more queries cached by virtue of simply having more people use it... in that way they dont need to delay while it fetches the record, somebody else has already done that in some cases so to you it appears quicker. typically that's where people might argue that its better.

at our size now though I'd say that's fairly moot but to me that's the only real legitimate thing one could say.. the more users use our servers.. the less of an issue that is too..
--
Marc - CEO/TekSavvy

I caught this thread and decided to re-run namebench...a while back I was having some trouble and switched everything over to Google DNS. Today's test results:

Fastest: TekSavvy
2nd: UltraDNS (31% slower than TSI)
3rd: Primus (35% slower)

Other notables...OpenDNS was 37% slower, Google DNS was 48% slower.

I've switched back to TekSavvy's servers as a result, so far working fine.

reply to TSI Marc
I'll switch back to the TSI servers and see how they perform now...

reply to TSI Marc
hmm..i get much worse performance with teksavvy DNS than with google :
using GRC nameserver benchmark :

206.248.142.222 | Min | Avg | Max |Std.Dev|Reliab%|
----------------+-------+-------+-------+-------+-------+
- Cached Name | 0.000 | 0.016 | 0.081 | 0.021 | 100.0 |
- Uncached Name | 0.055 | 0.196 | 0.514 | 0.111 | 100.0 |
- DotCom Lookup | 0.077 | 0.163 | 0.272 | 0.052 | 98.0 |
------+-------+-------+-------+-------+-------+

vs

8.8.8.8 | Min | Avg | Max |Std.Dev|Reliab%|
----------------+-------+-------+-------+-------+-------+
+ Cached Name | 0.000 | 0.019 | 0.082 | 0.023 | 100.0 |
+ Uncached Name | 0.047 | 0.165 | 0.440 | 0.101 | 100.0 |
+ DotCom Lookup | 0.048 | 0.166 | 0.283 | 0.060 | 100.0 |
------+-------+-------+-------+-------+-------+

reply to TSI Marc

yep. that's sort of how this is.. you kind of have to find a good balance based on the load that's on our servers.. there's no one size fits all kind of solution.

thanks for the input.
--
Marc - CEO/TekSavvy

reply to fluffybunny
Much worse?

the Cached avg response time is lower for us and the std deviation is also lower.

The uncached is faster for Google by 9ms but still something seems odd with this report as the overall response times are much higher than what I would normally expect on a normal Internet Connection.

I don't know GRC that well...it runs on Windows it looks like
--
TSI Gabe - TekSavvy Solutions Inc.
Authorized TSI employee ( »TekSavvy FAQ »Official support in the forum )

Alright, all servers are in production now

»tinyurl.com/9z899t3

Comparing our servers, 206.248.154.22 and 206.248.154.170 to OpenDNS and Google

And the clear winner is us
--
TSI Gabe - TekSavvy Solutions Inc.
Authorized TSI employee ( »TekSavvy FAQ »Official support in the forum )

I should probably add that this test is being run from my house from a normal DSL connection, this isn't something that's being run right next to the server that would yield an unfair advantage.

Here on the we(s)t coast, Google's DNS is the clear winner.

dig teksavvy.com @8.8.8.8
shows a query time of 25 msec.

whereas,

dig teksavvy.com @206.248.142.222
shows a query time of 74 msec

That's because Vancouver has separate DNS servers.

You need to use 76.10.191.198 & 199