I do not understand why AWS still encourages RAID configuration on EBS. I thought the volumes are replicated mutliple times within a single AZ. Optionally they can also be replicated to another AZ.
On GCP you don't need to do this RAID configuration. The documentation explicitly discourages this.
Quote: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/raid-config.html
Creating a RAID 0 array allows you to achieve a higher level of performance for a file system than you can provision on a single Amazon EBS volume. A RAID 1 array offers a "mirror" of your data for extra redundancy. Before you perform this procedure, you need to decide how large your RAID array should be and how many IOPS you want to provision.
Note, I am talking about safety / fault-tolerance in this question. I am not talking about performance, but at least from the GCP documentation they discourage striping disks together even for performance reasons:
Quote: https://cloud.google.com/compute/docs/disks
Compute Engine optimizes performance and scaling on persistent disks automatically. You don't need to stripe multiple disks together or pre-warm disks to get the best performance. When you need more disk space or better performance, resize your disks and possibly add more vCPUs to add more storage space, throughput, and IOPS
Just because the data is replicated multiple times within AZ, it doesn't mean the durability is 100%.
If you consider
gp2volume type, its durability is 99.8% - 99.9% which might not be the worst but compared to S3 that has 99.999999999% durability, it is lacking a bit.RAID 1 is indeed safer from the perspective of data durability. AWS is not telling you that this is the correct option, instead, it is one of the options if you need any. You can as well create EBS snapshots and/or use another data replication strategy (or you might be OK with the above-mentioned numbers in which case you don't need to do anything else beyond provisioning EBS volume in this regard).