When the instance is running, the EBS volumes are attached and fully usable. If the instance is stopped, the volumes stay attached but are not in use ( still possible to detach them safely). During a reboot, the volumes stay attached and nothing change. When the instance is terminated, the root volume is deleted if the " Delete on termination " is enabled (but additional volume stay unless you choose to delete them). Volumes can be attached or detached when the instance is running or stopped but detaching while running should be done carefully to avoid data loss.
Creating (volume is being created)
Available ( not attached to any instance)
Attaching ( in the process of attaching to an EC2 instance)
In use (attached to an EC2 instance & being processed)
Detaching ( in the process of being removed from an instance)
Deleting (volume is being deleted)
Deleted ( volume is completely removed)
They are slower for both data access and retrieval, as well as write operations, leading to longer wait times when saving, updating or retrieving data.