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Aren't they supposed to have 3 copies of everything? If so, two datacenters going offline at the same time should mean almost zero data loss.
by Dylan16807 17d ago
Aren't they supposed to have 3 copies of everything? If so, two datacenters going offline at the same time should mean almost zero data loss.
- dotancohen 17d agoNo. _You_ are supposed to have three copies of everything - and two of those should be off AWS.
- Dylan16807 17d agoYeah yeah I know about 3-2-1. But when I put data on normal S3, isn't my money supposedly paying for triple redundancy? Look, here's the documentation: https://docs.aws.amazon.com/AmazonS3/latest/userguide/DataDurability.html https://docs.aws.amazon.com/AmazonS3/latest/userguide/DataDu... "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." As far as I've heard before that's not with parity and three zones means three copies. But when I search now I see things about 5+4 parity, any insight here?
- cyberax 17d agoYes, normal S3 is at least triply-redundant. But it's possible for S3 to lose some data if two DCs are down and a disk dies in the single remaining DC. AWS doesn't use parity for S3, they actually mirror the data.
- cyberax 17d agoSome systems in AWS do, but they typically need a quorum of at least two copies to work. Other systems only have 2 copies. And in this case, it looks like all three DCs were damaged.