AWS AMI vs Snapshot: What's Better for Backups and Server Cloning?

When managing infrastructure on AWS, one of the most common tasks is creating backups or replicating environments. Two popular approaches are using EBS Snapshots and Amazon Machine Images (AMIs). While both serve as backup tools, their use cases differ significantly. This post dives deep into the differences, use cases, and when you should prefer one over the other, especially in production environments.

Step 1: Understand the Basics

What is an EBS Snapshot?

An EBS Snapshot is a block-level backup of an Elastic Block Store (EBS) volume. It captures everything stored on the volume at the time the snapshot is taken.

Key points:

• It includes all files, directories, and configurations present on the volume.
  
  

• Snapshots are incremental after the first full snapshot, which helps reduce storage costs.
  
  

What is an AMI?

An Amazon Machine Image (AMI) is a template that contains the application server configuration, OS, application code, and associated metadata required to launch an EC2 instance.

Key points:

• It includes one or more EBS volumes.
  
  

• It saves boot information, system configuration, and instance metadata.
  
  

Step 3: When to Use a Snapshot

You should use EBS snapshots when:

• You want to backup your web content in /var/www/html, config files in /etc/apache2/, or logs in /var/log/.
  
  

• You're storing database files and need to retain them for archival or audit.
  
  

• You're maintaining point-in-time backups of data volumes.
  
  

Snapshots are ideal for partial recovery, especially for non-root volumes.

Step 4: When to Use an AMI

Use AMI when:

• You want to replicate an entire production server including OS, web server (e.g., Apache/Nginx), configuration files, and application binaries.
  
  

• You plan to deploy identical EC2 instances at scale using Launch Templates or Auto Scaling Groups.
  
  

• You want to quickly recover or migrate an instance to another region or account.
  
  

In production environments, AMIs are preferred for disaster recovery and server cloning, as they provide a complete blueprint of a running system.

Step 5: How to Create and Use Each

Creating a Snapshot

1. Go to the EC2 console.
   
   

2. Select Volumes, choose the target volume.
   
   

3. Click Actions > Create Snapshot.
   
   

4. Provide a description and create it.
   
   

5. To restore: Create a volume from the snapshot and attach it to an instance.
   
   

Creating an AMI

1. Go to the EC2 console.
   
   

2. Select the running EC2 instance.
   
   

3. Click Actions > Image > Create Image.
   
   

4. Add name, description, and select volumes to include.
   
   

5. Once created, go to AMIs to launch a new instance.
   
   

Step 6: Pros, Cons, and Cautions

Pros of EBS Snapshots

• Lightweight and cost-effective.
  
  

• Incremental storage saves space.
  
  

• Easy to automate for data backup.
  
  

Cons of EBS Snapshots

• Cannot boot an EC2 instance directly.
  
  

• Manual steps needed to restore and configure the environment.
  
  

Pros of AMI

• Complete server backup including system configuration.
  
  

• Easy to clone and launch.
  
  

• Essential for automated scaling and failover.
  
  

Cons of AMI

• Larger in size, hence more costly than snapshots.
  
  

• AMIs must be manually updated if the system changes.
  
  

Caution:

• Always verify the contents after snapshot or AMI creation.
  
  

• Don’t rely solely on snapshots for full system recovery.
  
  

• Periodically test AMI restores to ensure they reflect the latest stable system state.
  
  

Use these methods at your own risk. In production systems, always test backups before assuming they are valid for disaster recovery.

Conclusion

Both AMI and EBS Snapshots are important tools in AWS infrastructure management. The choice between the two depends entirely on your use case.

• Need to backup only your Apache configurations or application data? Go with EBS Snapshots.
  
  

• Need to replicate your server environment or auto-scale? Choose AMIs.
  
  

A well-designed production system might use both: snapshots for data retention and AMIs for system replication.