Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Amazon EC2 instance store

An instance store provides temporary block-level storage for your instance. This storage is located on disks that are physically attached to the host computer. Instance store is ideal for temporary storage of information that changes frequently, such as buffers, caches, scratch data, and other temporary content. It can also be used to store temporary data that you replicate across a fleet of instances, such as a load-balanced pool of web servers.

An instance store consists of one or more instance store volumes exposed as block devices. The size of an instance store as well as the number of devices available varies by instance type.

The virtual devices for instance store volumes are ephemeral[0-23]. Instance types that support one instance store volume have ephemeral0. Instance types that support two instance store volumes have ephemeral0 and ephemeral1, and so on.

Instance store lifetime

You can specify instance store volumes for an instance only when you launch it. You can't detach an instance store volume from one instance and attach it to a different instance.

The data in an instance store persists only during the lifetime of its associated instance. If an instance reboots (intentionally or unintentionally), data in the instance store persists. However, data in the instance store is lost under any of the following circumstances:

Therefore, do not rely on instance store for valuable, long-term data. Instead, use more durable data storage, such as Amazon S3, Amazon EBS, or Amazon EFS.

When you stop, hibernate, or terminate an instance, every block of storage in the instance store is reset. Therefore, your data cannot be accessed through the instance store of another instance.

If you create an AMI from an instance, the data on its instance store volumes isn't preserved and isn't present on the instance store volumes of the instances that you launch from the AMI.

If you change the instance type, an instance store will not be attached to the new instance type. For more information, see Change the instance type.

Instance store volumes

The instance type determines the size of the instance store available and the type of hardware used for the instance store volumes. Instance store volumes are included as part of the instance's usage cost. You must specify the instance store volumes that you'd like to use when you launch the instance (except for NVMe instance store volumes, which are available by default). Then format and mount the instance store volumes before using them. You can't make an instance store volume available after you launch the instance. For more information, see Add instance store volumes to your EC2 instance.

Some instance types use NVMe or SATA-based solid state drives (SSD) to deliver high random I/O performance. This is a good option when you need storage with very low latency, but you don't need the data to persist when the instance terminates or you can take advantage of fault-tolerant architectures. For more information, see SSD instance store volumes.

The data on NVMe instance store volumes and some HDD instance store volumes is encrypted at rest. For more information, see Data protection in Amazon EC2.

Available instance store volumes

The following table provides the quantity, size, type, and performance optimizations of instance store volumes available on each supported instance type.

General purpose

Compute optimized

Memory optimized

Storage optimized

Accelerated computing

* Volumes attached to certain instances suffer a first-write penalty unless initialized. For more information, see Optimize disk performance for instance store volumes.

** For more information, see Instance store volume TRIM support.

† The c1.medium and m1.small instance types also include a 900 MB instance store swap volume, which may not be automatically enabled at boot time. For more information, see Instance store swap volumes.

To query instance store volume information using the Amazon CLI

You can use the describe-instance-types Amazon CLI command to display information about an instance type, such as its instance store volumes. The following example displays the total size of instance storage for all R5 instances with instance store volumes.

aws ec2 describe-instance-types \
    --filters "Name=instance-type,Values=r5*" "Name=instance-storage-supported,Values=true" \
    --query "InstanceTypes[].[InstanceType, InstanceStorageInfo.TotalSizeInGB]" \
    --output table

Example output

---------------------------
|  DescribeInstanceTypes  |
+----------------+--------+
|  r5ad.24xlarge |  3600  |
|  r5ad.12xlarge |  1800  |
|  r5dn.8xlarge  |  1200  |
|  r5ad.8xlarge  |  1200  |
|  r5ad.large    |  75    |
|  r5d.4xlarge   |  600   |
   . . .
|  r5dn.2xlarge  |  300   |
|  r5d.12xlarge  |  1800  |
+----------------+--------+

The following example displays the complete instance storage details for the specified instance type.

aws ec2 describe-instance-types \
    --filters "Name=instance-type,Values=r5d.4xlarge" \
    --query "InstanceTypes[].InstanceStorageInfo"

The example output shows that this instance type has two 300 GB NVMe SSD volumes, for a total of 600 GB of instance storage.

[
    {
        "TotalSizeInGB": 600,
        "Disks": [
            {
                "SizeInGB": 300,
                "Count": 2,
                "Type": "ssd"
            }
        ],
        "NvmeSupport": "required"
    }
]