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AWS EBS & EFS — Block and File Storage

AWS EBS & EFS — Block and File Storage

Beyond S3 (object storage), AWS offers two types of persistent storage for EC2 workloads:

EBS (Elastic Block Store) — Block storage attached to a single EC2 instance (like a hard drive)
EFS (Elastic File System) — Shared NFS file system accessible by many instances simultaneously

EBS — Elastic Block Store

EBS provides network-attached block storage for EC2 instances. It’s the primary storage for the OS disk and application data.

In Azure terms: EBS = Azure Managed Disks

EBS Volume Types

Type	Description	Use Case	Max IOPS
gp3 (General Purpose SSD)	Baseline 3,000 IOPS, configurable	Boot volumes, general workloads	16,000
gp2 (General Purpose SSD, older)	IOPS scales with size (3 IOPS/GB)	General workloads (prefer gp3)	16,000
io2 Block Express	High IOPS, 99.999% durability	Mission-critical databases	256,000
io1 (Provisioned IOPS SSD)	Consistent high IOPS	IOPS-intensive databases	64,000
st1 (Throughput Optimized HDD)	Low cost, sequential throughput	Big data, log processing	500 MB/s
sc1 (Cold HDD)	Lowest cost	Infrequently accessed data	250 MB/s

gp3 is the recommended default — better performance than gp2 at lower cost.

Key EBS Features

Feature	Description
Single-AZ	EBS volumes are tied to a specific AZ
Snapshots	Point-in-time backups stored in S3 (incremental)
Encryption	AES-256 via KMS — encrypt at creation
Multi-Attach	io1/io2 volumes can attach to up to 16 EC2 instances (same AZ)
Elastic Volumes	Resize, change type, or adjust IOPS without downtime

EBS Snapshots

# Create a snapshot
aws ec2 create-snapshot \
  --volume-id vol-0abc123 \
  --description "My backup snapshot"

# Copy snapshot to another region
aws ec2 copy-snapshot \
  --source-region us-east-1 \
  --source-snapshot-id snap-0abc123 \
  --destination-region eu-west-1 \
  --description "Cross-region backup"

# Create a volume from a snapshot
aws ec2 create-volume \
  --snapshot-id snap-0abc123 \
  --availability-zone us-east-1a \
  --volume-type gp3

EBS vs Azure Managed Disks

Feature	AWS EBS	Azure Managed Disks
SSD tiers	gp3, io2, io1	Standard SSD, Premium SSD, Ultra Disk
HDD tiers	st1, sc1	Standard HDD
Snapshots	Yes (S3-backed, incremental)	Yes (incremental)
Encryption	AES-256 via KMS	SSE via Azure Key Vault
Max size	64 TB	32 TB (most types)
Multi-attach	io1/io2 only (16 instances)	Ultra Disk (shared disks)

EFS — Elastic File System

EFS is a fully managed, scalable NFS (Network File System) that can be mounted by thousands of EC2 instances, containers (ECS/EKS), and Lambda functions simultaneously.

In Azure terms: EFS = Azure Files (NFS/SMB shares)

EFS vs EBS

Feature	EBS	EFS
Access	Single EC2 instance (usually)	Many instances simultaneously
Protocol	Block (mounted as disk)	NFS v4.1
AZ scope	Single AZ	Multi-AZ (Regional) or Single-AZ
Scaling	Manual resize (Elastic Volumes)	Automatic, scales to petabytes
Use case	OS disk, databases	Shared config, content, code
Pricing	Provisioned size	Pay per GB used

EFS Storage Classes

Class	Description
Standard	Frequently accessed files
Standard-IA	Infrequently accessed (lower cost, retrieval fee)
One Zone	Single AZ, lower cost
One Zone-IA	Single AZ + infrequent access

Lifecycle policies automatically move files to IA after 7, 14, 30, 60, or 90 days.

Mounting EFS

# Install EFS mount helper
sudo yum install -y amazon-efs-utils

# Mount EFS filesystem
sudo mount -t efs -o tls fs-0abc123:/ /mnt/efs

# Add to /etc/fstab for persistence
fs-0abc123:/ /mnt/efs efs defaults,_netdev,tls 0 0

EFS with ECS/EKS

EFS is commonly used as shared storage for containerized apps:

ECS: Mount EFS volumes in task definitions
EKS: Use the EFS CSI driver to create PersistentVolumes with ReadWriteMany access mode

Storage Decision Guide

Need	Choose
EC2 OS disk	EBS gp3
High-performance database	EBS io2
Shared files across many instances	EFS
Large object storage (files, backups, media)	S3
Long-term archive	S3 Glacier
On-prem files to cloud	AWS Storage Gateway

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