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).

Key Facts and Comparisons

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

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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.