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Comment by whatevaa

9 days ago

Yeah, I heard that consumer clouds are only locally redundant and there aren't even backups. So big DC damage could result in data loss.

By default, Amazon S3 stores data across at least separate datacenters that are in the same region, but are physically separate from each other:

Amazon S3 provides a highly durable storage infrastructure designed for mission-critical and primary data storage. S3 Standard, S3 Intelligent-Tiering, S3 Standard-IA, S3 Glacier Instant Retrieval, S3 Glacier Flexible Retrieval, and S3 Glacier Deep Archive redundantly store objects on multiple devices across a minimum of three Availability Zones in an AWS Region. An Availability Zone is one or more discrete data centers with redundant power, networking, and connectivity in an AWS Region. Availability Zones are physically separated by a meaningful distance, many kilometers, from any other Availability Zone, although all are within 100 km (60 miles) of each other.

You can save a little money by giving up that redundancy and having your data i a single AZ:

The S3 One Zone-IA storage class stores data redundantly across multiple devices within a single Availability Zone

For further redundancy you can set up replication to another region, but if I needed that level of redundancy, I'd probably store another copy of data with a different cloud provider so an AWS global failure (or more likely, a billing issue) doesn't leave my data trapped in one vendor).

I believe Google and Azure have similar levels of redundancy levels in their cloud storage.

What do you mean by "consumer clouds"?

  • I refer to stuff like onedrive/gdrive/dropbox.

    • It's certainly not the case for Google Drive, which is geo-replicated, and I would be very surprised if it's true for any other major cloud.

I mean… at the risk of misinterpreting sarcasm—

Except for the backup strategy said consumers apply to their data themselves, right?

If I use a service called “it is stored in a datacenter in Virginia” then I will not be surprised when the meteor that hits Virginia destroys my data. For that reason I might also store copies of important things using the “it is stored in a datacenter in Oregon” service or something.

  • You might expect backups in case of fire, though. Even if data is not fully up to date.