> Fundamentally however, giving clients control over when failover occurs means giving up control over failover.
Fundamentally the problem is that you want to direct a client to particular datacenter and it is not always shortest part (shortest != lowest latency) so anycast DNS isn't helping here.
There is reason biggest CDNs use it to direct to particular DC instead of "
just anycasting everything" like you're proposing, it's suboptimal.
> You're all probably familiar with 8.8.8.8 and 1.1.1.1,
And both companies behind that still direct you to particular datacenter, not anycasted IP, for the actual content.
Anycast IP are also "expensive", you need to use entire /24 route to get one, and it takes routing table space in every router's memory that is limited, and requires costly replacement if it runs out everywhere, not just where you distribute it.
Fundamentally the problem is that you want to direct a client to particular datacenter and it is not always shortest part (shortest != lowest latency) so anycast DNS isn't helping here.
There is reason biggest CDNs use it to direct to particular DC instead of " just anycasting everything" like you're proposing, it's suboptimal.
> You're all probably familiar with 8.8.8.8 and 1.1.1.1,
And both companies behind that still direct you to particular datacenter, not anycasted IP, for the actual content.
Anycast IP are also "expensive", you need to use entire /24 route to get one, and it takes routing table space in every router's memory that is limited, and requires costly replacement if it runs out everywhere, not just where you distribute it.