Mastering AWS Storage Types: Object, Block, and File

This study guide explores the fundamental differences between cloud storage architectures and their specific implementations within the AWS ecosystem, aligned with the SAA-C03 curriculum.

Learning Objectives

After studying this guide, you should be able to:

• Differentiate between Object, Block, and File storage architectures.
• Map specific AWS services (S3, EBS, EFS, FSx) to their respective storage categories.
• Identify the correct storage type based on requirements for latency, scalability, and shared access.
• Understand performance optimization techniques like RAID and storage tiering.

Key Terms & Glossary

• Amazon EBS (Elastic Block Store): High-performance block storage designed for use with Amazon EC2.
• Amazon S3 (Simple Storage Service): Scalable object storage used for backups, analytics, and static web hosting.
• Amazon EFS (Elastic File System): Serverless, fully managed file storage for Linux-based workloads.
• IOPS (Input/Output Operations Per Second): A measure of performance for storage devices like SSDs and HDDs.
• POSIX: A family of standards for maintaining compatibility between operating systems; EFS is POSIX-compliant.
• Metadata: Data about data (e.g., file size, creator, permissions). S3 allows up to 2 KB of custom metadata.

The "Big Idea"

In traditional computing, storage was simply a hard drive attached to a server. In the cloud, storage is disaggregated and specialized. Choosing the right storage is not just about capacity; it is a trade-off between how the OS sees the data (Block), how many users share the data (File), and how much metadata you need to manage (Object).

Formula / Concept Box

Hierarchical Outline

1. Block Storage (The "Local" Disk)
   • Characteristics: Managed by OS filesystem (NTFS, Ext4); Low latency; Fixed capacity.
   • AWS Implementation: Amazon EBS (Persistent) and Instance Store (Ephemeral).
   • Performance: Measured in IOPS and Throughput.
2. Object Storage (The "Web" Storage)
   • Characteristics: Flat hierarchy (Key-Value); Metadata-rich; Accessible via URL.
   • AWS Implementation: Amazon S3.
   • Features: Lifecycles, Versioning, and Storage Classes (Standard, Glacier).
3. File Storage (The "Shared" Drive)
   • Characteristics: Hierarchical (folders/subfolders); Simultaneous multi-instance access.
   • AWS Implementation:
     • EFS: Linux/NFS focus.
     • FSx: Specialized for Windows (SMB), Lustre (HPC), or NetApp ONTAP.

Visual Anchors

Storage Selection Logic

Visualization of Data Structures

\begin{center} \begin{tikzpicture} % Block Storage Box \draw[thick] (0,3) rectangle (3,5); \node at (1.5,5.3) {\textbf{Block Storage (EBS)}}; \draw (0.2,3.2) rectangle (0.8,3.8); \draw (1.2,3.2) rectangle (1.8,3.8); \draw (2.2,3.2) rectangle (2.8,3.8); \draw (0.2,4.2) rectangle (0.8,4.8); \draw (1.2,4.2) rectangle (1.8,4.8); \draw (2.2,4.2) rectangle (2.8,4.8); \node[scale=0.7] at (1.5,2.8) {Fixed Segments (Blocks)};

% Object Storage Box \draw[thick] (5,3) rectangle (8,5); \node at (6.5,5.3) {\textbf{Object Storage (S3)}}; \draw[fill=gray!20] (5.5,3.5) circle (0.4cm) node[scale=0.6] {Data}; \draw[fill=gray!20] (7.2,4.3) circle (0.5cm) node[scale=0.6] {Metadata}; \node[scale=0.7] at (6.5,2.8) {Flat Namespace (ID/Key)}; \end{tikzpicture} \end{center}

Definition-Example Pairs

• Ephemeral Storage: Temporary storage that is deleted when the instance stops.
  • Example: EC2 Instance Store used for swap files or temporary caches.
• Write-Once/Read-Many (WORM): Data that cannot be altered once written.
  • Example: S3 Object Lock used for regulatory compliance to prevent file deletion.
• Data Striping (RAID 0): Spreading data across multiple disks to increase performance.
  • Example: Combining two 500 GiB EBS volumes into a 1 TiB RAID 0 array to double the IOPS for a database.

Worked Examples

Example 1: Constructing an S3 URL

You have a file named report.pdf in a bucket named finance-dept. What is the virtual-hosted style URL?

1. Pattern: bucketname.s3.region.amazonaws.com/filename
2. Result: https://finance-dept.s3.us-east-1.amazonaws.com/report.pdf

Example 2: Shared Storage for a Web Fleet

A fleet of 10 Linux EC2 instances needs to share a common directory of user-uploaded images.

• Solution: Mount an Amazon EFS volume to all 10 instances.
• Reasoning: S3 is too slow for frequent small file writes, and EBS volumes can only be attached to one instance at a time (unless using specific Multi-Attach IOPS volumes, which have OS limitations).

Checkpoint Questions

1. Which storage type provides a "flat surface" for data and uses a Unique ID for retrieval?
2. True or False: Amazon EBS volumes provide durability by automatically replicating data across multiple Availability Zones.
3. What is the standard delimiter used in S3 to mimic a directory structure?
4. If you need a high-performance filesystem for a Windows-based application using the SMB protocol, which service should you choose?

▶Click to see answers

1. Object Storage (Amazon S3).
2. False. EBS volumes are replicated within a single Availability Zone (S3 is the one replicated across multiple AZs).
3. The forward slash ( / ).
4. Amazon FSx for Windows File Server.