AwsComparisonBeginner · 4 min read

EBS vs Instance Store in AWS: Key Differences and Usage Guide

In AWS, EBS (Elastic Block Store) provides persistent, network-attached storage that retains data after instance stops, while Instance Store offers temporary, physically attached storage that is lost if the instance stops or terminates. Use EBS for durable storage and Instance Store for high-speed, temporary data needs.

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Quick Comparison

Here is a quick side-by-side comparison of EBS and Instance Store in AWS based on key factors.

Factor	EBS (Elastic Block Store)	Instance Store
Storage Type	Network-attached block storage	Physically attached ephemeral storage
Persistence	Data persists after instance stops/terminates	Data lost on instance stop/terminate
Performance	Consistent, scalable IOPS with SSD/HDD options	Very high I/O performance, low latency
Use Case	Durable storage for OS, databases, backups	Temporary storage for caches, buffers, scratch data
Cost	Charged per GB provisioned and I/O	Included with instance, no extra charge
Availability	Can be detached and reattached to instances	Tied to lifecycle of the instance

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Key Differences

EBS volumes are network-attached storage devices that persist independently of the life of an EC2 instance. This means if you stop or terminate your instance, the data on the EBS volume remains intact and can be reattached to another instance. This makes EBS ideal for storing important data like operating systems, databases, and application files.

In contrast, Instance Store is physically attached storage that exists only during the lifetime of the instance. When the instance stops or terminates, all data on the Instance Store is lost. However, because it is directly attached, it offers very high input/output performance and low latency, making it suitable for temporary data like caches or buffers.

Another difference is cost and flexibility. EBS volumes incur additional charges based on size and performance, but you can resize and snapshot them. Instance Store comes included with certain instance types but cannot be detached or resized independently.

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EBS Volume Example

terraform

resource "aws_ebs_volume" "example" {
  availability_zone = "us-east-1a"
  size              = 10
  type              = "gp3"
}

resource "aws_volume_attachment" "example_attach" {
  device_name = "/dev/xvdf"
  volume_id   = aws_ebs_volume.example.id
  instance_id = "i-0123456789abcdef0"
}

Output

Creates a 10 GiB gp3 EBS volume and attaches it to the specified EC2 instance at /dev/xvdf.

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Instance Store Equivalent

bash

# Launch EC2 instance with instance store volumes
aws ec2 run-instances \
  --image-id ami-0abcdef1234567890 \
  --count 1 \
  --instance-type m5d.large \
  --block-device-mappings '[{"DeviceName":"/dev/xvdb","VirtualName":"ephemeral0"}]' \
  --key-name MyKeyPair \
  --subnet-id subnet-6e7f829e

Output

Starts an EC2 instance of type m5d.large with one instance store volume attached as /dev/xvdb.

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When to Use Which

Choose EBS when you need durable, persistent storage that survives instance stops and terminations, such as for databases, system disks, or important files. It is also best when you want to take snapshots or resize storage easily.

Choose Instance Store when you require very fast, temporary storage for data that can be lost without issue, like caches, buffers, or scratch space during processing. It is included with some instance types and offers low latency but no data persistence.

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Key Takeaways

EBS provides persistent, network-attached storage that keeps data after instance stops.

Instance Store offers fast, temporary storage lost on instance stop or termination.

Use EBS for important data and Instance Store for temporary, high-speed needs.

EBS volumes can be detached, resized, and snapshotted; Instance Store cannot.

Instance Store is included with some instance types at no extra cost.