Diferença entre disco local e EBS

EBS is like the virtual disk of a VM:

   Durable, instances backed by EBS can be freely started and stopped (saving money)
   Can be snapshotted at any point in time, to get point-in-time backups
   AMIs can be created from EBS snapshots, so the EBS volume becomes a template for new systems

Instance storage is:

   Local, so generally faster
   Non-networked, in normal cases EBS I/O comes at the cost of network bandwidth (except
   Has limited I/O per second IOPS). Even provisioned I/O maxes out at a few thousand IOPS
   Fragile. As soon as the instance is stopped, you lose everything in instance storage.

Here's where to use each:

   Use EBS for the backing OS partition and permanent storage (DB data, critical logs, application config)
   Use instance storage for in-process data, noncritical logs, and transient application state. Example: external sort storage, tempfiles, etc.
   Instance storage can also be used for performance-critical data, when there's replication between instances (NoSQL DBs, distributed queue/message systems, and DBs with replication)
   Use S3 for data shared between systems: input dataset and processed results, or for static data used by each system when lauched.
   Use AMIs for prebaked, launchable servers