AWS Storage Types: Object, Block, and File Storage Characteristics

This guide explores the fundamental storage architectures available in the cloud, specifically mapping them to AWS services like Amazon EBS, S3, and EFS/FSx. Understanding these characteristics is critical for the SAA-C03 exam.

Learning Objectives

After studying this guide, you should be able to:

• Differentiate between block, file, and object storage architectures.
• Identify the appropriate AWS service (EBS, EFS, FSx, S3) for specific technical requirements.
• Analyze workloads to determine if they require low-latency (block), shared-hierarchy (file), or massive-scale (object) storage.
• Map access protocols (NFS, SMB, HTTP, iSCSI) to their respective storage types.

Key Terms & Glossary

• Block Storage: Data is broken into fixed-size chunks (blocks) without metadata; managed by an Operating System (OS).
• Object Storage: Data is stored as discrete units (objects) in a flat address space, including the data, metadata, and a unique identifier.
• File Storage: Data is organized in a hierarchical structure of folders and files.
• IOPS (Input/Output Operations Per Second): A performance metric for block storage measuring how many reads/writes occur per second.
• POSIX: A set of standards for maintaining compatibility between operating systems, often required for file-level storage.
• NFS (Network File System): A protocol used primarily by Linux for shared file access.

The "Big Idea"

In AWS, the choice of storage is a trade-off between performance (latency), access patterns (shared vs. local), and scalability (cost/capacity). Block storage is like a raw hard drive attached to one computer; File storage is like a shared network folder for a team; Object storage is like a massive, infinite digital warehouse where every item has a unique barcode.

Formula / Concept Box

Hierarchical Outline

• I. Block Storage (Amazon EBS)
  • Structure: Divided into blocks; requires a filesystem (NTFS/ext4) to be usable by an OS.
  • Connectivity: Low-latency, high-performance; usually attached to one EC2 instance at a time.
  • Volume Types: SSD (IOPS intensive) and HDD (Throughput intensive).
• II. File Storage (Amazon EFS & FSx)
  • Structure: Hierarchical directory tree; supports concurrent access from many instances.
  • Protocols: EFS uses NFS (Linux); FSx for Windows uses SMB.
  • Characteristics: POSIX-compliant; data is stored across multiple Availability Zones for durability.
• III. Object Storage (Amazon S3)
  • Structure: Flat hierarchy using Buckets and Keys; no "folders" (prefixes are used to simulate them).
  • Metadata: Each object can have up to 2KB of metadata (system and user-defined).
  • Access: Accessed via REST API (GET/PUT); globally accessible via URL.

Visual Anchors

Storage Selection Decision Tree

Conceptual Architecture

\begin{tikzpicture}[scale=0.8] % Block Storage \draw[thick] (0,3) rectangle (3,4) node[midway] {\small Block 1}; \draw[thick] (0,2) rectangle (3,3) node[midway] {\small Block 2}; \draw[thick] (0,1) rectangle (3,2) node[midway] {\small Block 3}; \node at (1.5,4.5) {\textbf{Block (EBS)}};

% File Storage \draw[thick] (5,4) -- (4,3); \draw[thick] (5,4) -- (6,3); \draw[thick] (4,3) -- (3.5,2); \draw[thick] (4,3) -- (4.5,2); \node[draw,circle,inner sep=1pt] at (5,4) {\tiny root}; \node at (5,4.5) {\textbf{File (EFS)}};

% Object Storage \draw[thick, fill=gray!20] (9,2.5) circle (1.2); \node at (9,2.8) {\tiny Data}; \node at (9,2.2) {\tiny Metadata}; \node at (9,4.5) {\textbf{Object (S3)}}; \end{tikzpicture}

Definition-Example Pairs

• Metadata: Data about data. Example: An S3 object for an image might contain metadata specifying the camera model used and the date the photo was taken.
• Shared File System: A storage system that allows multiple servers to read/write simultaneously. Example: 10 different web servers all accessing the same 'images' folder to display product photos on a website via EFS.
• Ephemeral Storage: Non-persistent storage that is lost if an instance is stopped. Example: EC2 Instance Store used for temporary buffers and caches.

Worked Examples

Scenario 1: High-Performance Database

Requirement: You are running a PostgreSQL database on an EC2 instance that requires sub-millisecond latency for transaction logs. Solution: Amazon EBS (Provisioned IOPS SSD).

• Why? Databases require block-level access to manage their own data structures and need the lowest possible latency which only block storage provides.

Scenario 2: Massive Media Archive

Requirement: A company needs to store 500 TB of video files that are rarely accessed but must be available within minutes if requested. Solution: Amazon S3 (S3 Glacier Instant Retrieval).

• Why? S3 provides the scale needed for 500 TB without managing volumes, and Glacier tiers offer significant cost savings for infrequently accessed data.

Checkpoint Questions

1. Which storage type uses a REST API (HTTP) for data retrieval instead of a local filesystem mount?
2. True or False: Amazon EFS can be accessed by both Linux and Windows instances using the NFS protocol.
3. What is the maximum size of metadata that can be attached to an S3 object?
4. If you need to share a file system between multiple EC2 instances using the SMB protocol, which service should you use?

▶Click to see answers

1. Object Storage (Amazon S3).
2. False. EFS is for Linux (NFS). For Windows (SMB), use Amazon FSx.
3. 2 KB.
4. Amazon FSx for Windows File Server.