EC2 Storage: EBS Volumes and Instance Store

Every EC2 instance needs storage — for the operating system, application data, logs, and temporary files. AWS provides two primary categories of block storage for EC2: Amazon EBS (Elastic Block Store) for persistent, network-attached storage and Instance Store for high-performance, ephemeral local storage. This lesson covers both in detail.

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Amazon EBS (Elastic Block Store)

What Is EBS?

Amazon EBS provides persistent block-level storage volumes that you attach to EC2 instances. Think of an EBS volume as a virtual hard drive in the cloud.

Key characteristics:

• Network-attached — EBS volumes connect to instances over the network (within the same AZ)
• Persistent — data survives instance stops, restarts, and even termination (if configured)
• Snapshots — you can back up volumes to S3 as point-in-time snapshots
• Encryption — supports encryption at rest using AWS KMS
• Elastic — you can resize volumes and change types without downtime (in most cases)

EBS Volume Types

AWS offers several EBS volume types, each optimised for different performance and cost requirements:

Volume Type	Category	Max IOPS	Max Throughput	Use Cases
gp3	General Purpose SSD	16,000	1,000 MiB/s	Boot volumes, dev/test, most workloads
gp2	General Purpose SSD	16,000	250 MiB/s	Legacy default; use gp3 for new volumes
io2 Block Express	Provisioned IOPS SSD	256,000	4,000 MiB/s	Mission-critical databases, SAP HANA
io1	Provisioned IOPS SSD	64,000	1,000 MiB/s	Databases needing consistent IOPS
st1	Throughput Optimised HDD	500	500 MiB/s	Big data, data warehouses, log processing
sc1	Cold HDD	250	250 MiB/s	Infrequently accessed data, lowest cost

gp3 vs gp2

gp3 is the current recommended general-purpose volume:

Feature	gp3	gp2
Baseline IOPS	3,000 (independent of size)	3 IOPS per GiB (min 100, max 16,000)
Baseline throughput	125 MiB/s (independent of size)	Scales with IOPS
Provisioned IOPS	Up to 16,000 (additional cost)	Not configurable separately
Cost	~20% cheaper than gp2 at baseline	Higher baseline cost

Best practice: Use gp3 for new volumes. It provides better baseline performance at a lower cost than gp2.

Provisioned IOPS (io2 / io1)

For workloads that need guaranteed, consistent IOPS regardless of volume size:

# Create an io2 volume with 10,000 provisioned IOPS
aws ec2 create-volume \
  --volume-type io2 \
  --size 100 \
  --iops 10000 \
  --availability-zone us-east-1a

io2 Block Express (available on Nitro-based instances) supports up to 256,000 IOPS and 4,000 MiB/s throughput — suitable for the most demanding database workloads.

EBS Multi-Attach

io2 and io1 volumes support Multi-Attach, allowing a single volume to be attached to up to 16 Nitro-based instances in the same AZ simultaneously. This is useful for clustered applications that need shared block storage (e.g., Oracle RAC).

EBS Snapshots

An EBS snapshot is a point-in-time backup of an EBS volume, stored in Amazon S3 (managed by AWS — you do not see the snapshots in your S3 buckets).

# Create a snapshot
aws ec2 create-snapshot \
  --volume-id vol-0123456789abcdef0 \
  --description "Pre-upgrade backup"

# Create a volume from a snapshot (can be in a different AZ)
aws ec2 create-volume \
  --snapshot-id snap-0123456789abcdef0 \
  --availability-zone us-east-1b \
  --volume-type gp3

# Copy a snapshot to another region (for disaster recovery)
aws ec2 copy-snapshot \
  --source-snapshot-id snap-0123456789abcdef0 \
  --source-region us-east-1 \
  --destination-region eu-west-1

Key snapshot features: