I feel like I periodically research “How much does it cost to use instance store a.k.a Ephemeral Disk (volatile disk) available on AWS EC2?”, but instance store can be used for free.

First, let’s read the official AWS documentation.

• Official documentation: Amazon EC2 インスタンスストア - Amazon Elastic Compute Cloud

Most EC2 instances have a disk area called instance store (ephemeral store). Unlike EBS, this area has advantages such as no charges for disk I/O.

• Source: ［AWS失敗と対策］仮想マシンの停止/起動でデータが消える | 日経 xTECH（クロステック）

What is Instance Storage

• Features – Local disk of EC2 physical chassis – Size, number, HDD/SSD are predetermined by EC2 instance type

• Advantages – Free! – Any file system can be used – Less affected by network (latency and bandwidth) because it’s a local disk

• Cautions – Data is deleted when you stop the instance [Important] Data is not lost on reboot – No snapshot function – Cannot be attached to another EC2 instance

If you want to use instance store later, read the following article:

• Instance Store(Ephemeral Disk)を後から使用する ｜ DevelopersIO

Finally, once you understand instance store, it would be good to grasp all the storage available on AWS next.

• ストレージ - Amazon Elastic Compute Cloud

That’s all from the Gemba where I thought “Was the usage fee for AWS EC2 instance store free?”