Instance Store

Amazon EC2 instances use Amazon Elastic Block Store (EBS) or Instance Store volumes as their root volumes. When an Instance Store-backed EC2 instance is terminated, its data is lost permanently. Understanding EBS vs. Instance Store is crucial for managing persistent data, backups, and disaster recovery.

This guide covers: ✔ Understanding Instance Store vs. EBS Volumes ✔ What Happens to Data on Termination? ✔ Best Practices for Data Persistence ✔ SecureCart Use Case: Managing Web Application Storage ✔ Common Mistakes & How to Avoid Them

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🔹 Understanding Instance Store vs. EBS Volumes

Volume Type	Persistent Storage?	Attached To?	Use Case
Instance Store	❌ No	Specific EC2 instance	High-performance temporary storage (e.g., cache, buffer)
Amazon EBS	✅ Yes	Any EC2 instance in the same AZ	Persistent storage for OS, databases, logs

🔹 Key Difference:

• Instance Store is ephemeral (data is lost when the instance stops or terminates).

• EBS Volumes persist beyond instance lifecycle unless manually deleted.

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🔹 What Happens to Data on Termination?

Instance Type	Data Behavior on Termination
Instance Store-backed AMI	🚨 All data is lost permanently
EBS-backed AMI	✅ Root volume deleted (unless "Delete on Termination" is disabled)
Attached EBS Volumes (non-root)	✅ Data persists

✅ How to Check If Your EC2 Instance is Using Instance Store?

1. Navigate to EC2 Console → Select the Instance.

2. Check Storage Type under Instance Details.

3. If the root volume is Instance Store, data will be lost on termination.

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🔹 SecureCart Use Case: Managing Web Application Storage

SecureCart, an e-commerce platform, hosts its web application on EC2 and needs persistent storage for user sessions, logs, and database records.

✅ SecureCart’s Storage Needs: ✔ Web application files must persist even after instance termination. ✔ Application logs should not be lost (used for debugging and compliance). ✔ Product images must be stored safely for quick retrieval.

🔹 What SecureCart Uses: ✔ Amazon EBS for persistent storage of logs, application code, and configurations. ✔ Amazon S3 for product images & backups (cheaper and more scalable). ✔ Amazon RDS for transactional data (instead of self-managed database on EC2).

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🔹 Best Practices for Data Persistence

1️⃣ If Using Instance Store: Take Regular Backups

✔ Store critical files in Amazon S3 or Amazon EFS before termination. ✔ Use Amazon FSx or EFS for shared storage between multiple instances.

2️⃣ Convert Instance Store to EBS for Persistence

✅ Steps to Migrate Data from Instance Store to EBS:

1. Create an Amazon Machine Image (AMI) from the existing instance.

2. Launch a new EC2 instance using an EBS-backed AMI.

3. Attach an EBS volume and copy critical data from the instance store.

3️⃣ Modify EBS "Delete on Termination" Flag

By default, EBS root volumes are deleted when an instance is terminated.

✅ Steps to Keep Data After Termination:

1. Go to EC2 Console → Select the instance.

2. Under Storage, find the EBS volume.

3. Modify Delete on Termination to ❌ Disabled.

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🔹 Common Mistakes & How to Avoid Them

Mistake	Impact	Solution
Using Instance Store for critical data	Data lost on instance termination	Use EBS or S3 for persistent storage
Not backing up instance store data	Permanent loss of application files	Create regular S3 backups
Leaving EBS "Delete on Termination" enabled	Root volume lost with instance	Disable Delete on Termination for persistent storage
Assuming Instance Store can be detached & reattached	Cannot recover data after instance termination	Use EBS for detachable storage

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✅ Summary

✔ Instance Store is ephemeral; all data is lost on termination. ✔ EBS is persistent; data remains unless explicitly deleted. ✔ SecureCart uses EBS for application storage & S3 for backups. ✔ Modify "Delete on Termination" settings to retain EBS volumes. ✔ Convert Instance Store-backed AMIs to EBS-backed AMIs for persistence.