1th of 2 Questions.
What is the local EC2 instance store?
Local Instance Store Mechanics
The 'local' instance store refers to the fact that the storage is directly mapped to the physical host hardware running your virtual machine. When you launch an instance type that includes an instance store (often called ephemeral storage), AWS provisions the disk directly on the local physical server.
Critical Limitations
Data Persistence: Data does not persist across stop/start cycles. Only a reboot allows the data to survive.
No Snapshots: Unlike EBS, you cannot take native snapshots of instance store volumes.
Use Case Suitability: Best for distributed filesystems or applications that replicate data across multiple instances, ensuring that if one node fails, data is available elsewhere.