What happens to the data stored in an instance store if the EC2 instance is stopped?

When an EC2 instance that uses instance store is stopped, the data stored in the instance store is lost. Instance store provides temporary storage that is physically attached to the host machine, which means that it is ephemeral in nature. When the EC2 instance is stopped, AWS completely shuts down the underlying host, and associated instance store data does not persist beyond the lifecycle of that instance.

In contrast to other storage options like Elastic Block Store (EBS), which retains data even when stopped, instance store is specifically designed to be temporary, making it suitable for data that can be regenerated or does not need to be preserved across instance states.

So, if you are using instance store, it is crucial to implement mechanisms to persist important data elsewhere (like EBS volumes or cloud storage options) to avoid any data loss during operations that stop the instance.