EBS volume types and instance store: gp3 vs io2 Block Express vs st1 and sc1

Amazon Elastic Block Store (EBS) provides network-attached block storage volumes for EC2, behaving like virtual hard disks. A volume lives in one Availability Zone (AZ), is replicated within that AZ to protect against a single hardware failure, persists independently of the instance and can be backed up with point-in-time snapshots stored in Amazon S3. Normally a volume attaches to one instance at a time; io1 and io2 volumes support Multi-Attach to several Nitro-based instances in the same AZ, for clustered applications that coordinate concurrent writes themselves. Because a volume is tied to one AZ, moving data to another AZ means creating a snapshot and restoring it there.