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Some EC2 storage secretly deletes your data when you turn the server off
💡 Instance store is fast but disappears when the instance stops; EBS is a persistent virtual drive that survives, detaches, and snapshots.
Not all disk storage on AWS survives a reboot. Every EC2 instance can use two very different kinds of storage, and mixing them up is one of the most painful beginner surprises. Instance store is a temporary disk physically attached to the host machine your server runs on. It's fast and free, but it's ephemeral — the moment you stop or terminate the instance, everything on it is wiped forever.
The durable alternative is Amazon EBS (Elastic Block Store). Think of it as a virtual hard drive that lives independently of any single server. You can detach an EBS volume from one instance and attach it to another, and the data persists even when the instance is stopped. Because it survives the instance's life, EBS is where you keep anything you actually care about — databases, application files, logs.
EBS also lets you take snapshots: point-in-time backups stored in S3 behind the scenes. From a snapshot you can restore a volume, or spin up an identical one in another Availability Zone. This is how teams get durability and recover from failures without babysitting hardware.
The practical rule: use EBS for anything that must outlive the instance, and treat instance store as scratch space for caches or temporary computation you can afford to lose.