> Back in the day, we used to talk a lot about how RAID is not a backup strategy. The modern version of that is that S3 is not a backup strategy.
This is not remotely the same thing. A RAID offers no protection against logical corruption from an erroneous script or even something as simple as running a truncate on the wrong table. Having a backup of your database in a different storage medium on the same cloud provider protects from vastly more failure modes.
> Who the hell doesn't have offsite backups?
No one. But S3 is already storing your data in three different data centers even if you have a single bucket in one region, and you also have SQL log replication to another region. Multi-region is as easy as enabling replication but that is only available within a single cloud provider (I can't replicate RDS to Google Cloud SQL, only to another RDS region). I would guess that a lot of people use that rather than using a different cloud provider.
> This is not remotely the same thing. A RAID offers no protection against logical corruption from an erroneous script [...] But S3 is already storing your data in three different data centers
That sounds like...the same argument?
A RAID array stores your data on multiple physical drives in the machine, but offers no protection against logical corruption (where you store the same bad data on every drive), destruction of the machine, or loss of access to the machine.
S3 stores your data in multiple physical data centres in the region, but offers no protection against logical corruption, downtime of the entire region, or loss of access to the cloud.
You can't count replicas as providing durability against any threat that will apply equally to all the replicas.
This is not remotely the same thing. A RAID offers no protection against logical corruption from an erroneous script or even something as simple as running a truncate on the wrong table. Having a backup of your database in a different storage medium on the same cloud provider protects from vastly more failure modes.
> Who the hell doesn't have offsite backups?
No one. But S3 is already storing your data in three different data centers even if you have a single bucket in one region, and you also have SQL log replication to another region. Multi-region is as easy as enabling replication but that is only available within a single cloud provider (I can't replicate RDS to Google Cloud SQL, only to another RDS region). I would guess that a lot of people use that rather than using a different cloud provider.