3 ms·
> Ycombinator.com, why do you have a TTL of 12 seconds? You either meant to say 60 seconds, or forgot to factor your local caching DNS resolver in. Here: $
by aexaey 10y ago
> Ycombinator.com, why do you have a TTL of 12 seconds?
You either meant to say 60 seconds, or forgot to factor your local caching DNS resolver in. Here:
$ dig +short soa ycombinator.com
ns-225.awsdns-28.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
$ dig a ycombinator.com @ns-225.awsdns-28.com. | grep -A3 'ANSWER SECTION'
;; ANSWER SECTION:
ycombinator.com. 60 IN A 54.240.184.14
ycombinator.com. 60 IN A 54.240.184.154
ycombinator.com. 60 IN A 54.240.184.206
That said, 60 seconds is still ridiculously low.
- babo 10y agoNot so for CDN content.
- aexaey 10y agoCare to elaborate how/why exactly CDN would be different here?
- babo 10y agoCDN providers has a highly volatile infrastructure setup, short TTL helps them to dynamically reallocate resources. Just as an example, cache invalidation could be implemented with a switch of DNS records.
- deleted 10y ago[deleted]
- bogomipz 10y ago>"CDN providers has a highly volatile infrastructure setup" No they don't. CDNs with the exception of AWS Cloudfront don't run on a cloud provider. Things aren't quickly spun up and down with any kind of velocity. CDNs manage all of their own infrastructure, POPs, hardware etc. There is usually a maximal hardware lifecycle since the CDN business is so CapEx heavy. Cache-Control TTLs and DNS SOA record TTLs have nothing to do with each other. They are separate layer 7 concerns. The former is used by your browser and the latter by your system's resolver library. I have never heard of anybody using SOA TTLs records to purge a cache. How would that even work? CDNs generally give you decent tools to purge your objects. Source: I worked for a CDN.