Hacker News Reader

> I don't know of a single enterprise customer that doesn't have their data replicated to two datacenters, and then backed up to some other medium (tape or disk-based backup appliance) for anything business critical.

Longtime consultant here with BCP/DR insight into 20+ large F500 companies... I think you would be seriously surprised at how common it is for even enterprise customers to not bother with multi-DC or even offsite backups. And even among the ones that do, many of the ones that are non-cloud-based are so immature at it that I would not put money on their backups being restorable if needed. And this is even more true for your “we’re a startup, we don’t have time to worry about backing up our data!” companies, which are in abundance.

For a small peak, go look at how many people were freaking out about losing their entire business due to the loss of a single OVH data center.

Of course, as a consultant I do naturally skew towards customers that need help with this stuff, so my perspective is probably biased towards the companies that are worse off in this regard. But they’re definitely out there.

Giving him the benefit of the doubt that he knows his own customers here.

He said:

> Most of our customers, if they have on-premises systems—if they're lucky—can store two objects in the same data center

You said:

> I don't know of a single enterprise customer that doesn't have their data replicated to two datacenters

His customers don't equal your enterprise customers. You are both right most likely.

Given that part of what I do is help enterprise customers with cloud adoption, almost all of whom are fortune 500 (and on his radar), with an AWS presence, I strongly doubt it.

> I don't know of a single enterprise customer that doesn't have their data replicated to two datacenters, and then backed up to some other medium (tape or disk-based backup appliance) for anything business critical.

You snipped out the part of the quote that answers your question.

"Most of our customers, if they have on-premises systems—if they're lucky—can store two objects in the same data center, which gives them four 9s. If they're really good, they may have two data centers and actually know how to replicate over two data centers, and that gives them five 9s. But eleven 9's, in terms of durability, is just unparalleled. And it trumps everything."

> I don't know of a single enterprise customer that doesn't have their data replicated to two datacenters...

Except, in AWS' case, each AZs (Availability Zones) is made up of upto 8 DCs (Data Centers), and each full-region has at least 3 AZs and 2 Transit Centers. Amazon S3 replicates data to 3 different AZs (which, I am guessing, is in addition to replicating it across DCs in a single AZ for 'eleven 9s').

With S3 cross-region replication durability may shoot up to 'sixteen 9s'? 100% durability, if it exists, is something the major Cloud providers are yet to offer?

ref: https://maisonbisson.com/post/object-storage-prior-art-and-l...

>You snipped out the part of the quote that answers your question.

Replicating across two datacenters isn't "really good" though, that's considered table stakes.

>Except, in AWS' case, each AZs (Availability Zones) is made up of upto 8 DCs (Data Centers), and each full-region has at least 3 AZs and 2 Transit Centers. Amazon S3 replicates data to 3 different AZs (which, I am guessing, is in addition to replicating it across DCs in a single AZ for 'eleven 9s').

In AWS' case, the 8 DCs in an AZ are directly adjacent which isn't really useful for anything beyond metro (active/active) availability. I haven't seen a DR plan that doesn't have a hard requirement for the secondary copy of data to be outside of the metro loop/blast radius generally in a different state.