Benefits of EBS-Backed vs Instance Store EC2 Instances

Choosing the right storage option for your Amazon EC2 instances is crucial for optimizing performance, cost, and durability. You may find yourself torn between using EBS-backed instances or instance store-backed instances. Let’s dig into why EBS-backed instances are often the best choice for most users, while also investigating scenarios where an instance store could be more suitable.

Why Choose EBS-Backed Instances?

Here are some compelling reasons to favor EBS (Elastic Block Store) over instance store for your EC2 instances:

• Control Over Instance Termination: EBS-backed instances offer the flexibility to configure the deletion behavior upon termination, protecting your data from accidental loss. This feature is not available with instance stores, where all data is lost when the instance is stopped or terminated.

• Stop and Start Instances: With EBS, you can stop your instance anytime, saving costs because you’re billed primarily for the data stored and not for running resources when the instance is inactive. You can restart it later without losing data, unlike instance store-backed instances.

• Persistent Storage: EBS volumes are independent of the lifecycle of the instance, so your data persists even if the instance crashes. This feature is invaluable for faster recovery and enhanced data durability.

• Flexible Resizing: You can dynamically resize your EBS volumes to fit changing needs, adding storage or increasing throughput as required without downtime. Instance store volumes are fixed in size and cannot be resized.

• Migrating Instances: Easily detach an EBS volume from one instance and attach it to another. This is particularly useful if the underlying hardware becomes faulty or requires migration due to scheduled maintenance.

• Faster Launch Times: Launching an EBS-backed instance is quicker because the root volume doesn’t need to be loaded from an S3-backed AMI, unlike with instance store-backed instances.

AWS instances might need migration due to scheduled hardware maintenance. Stopping and starting an EBS-backed instance helps swap it to new hardware seamlessly.

Considerations and Precautions

While EBS is generally the better choice, it’s not infallible. Here’s what you should consider:

• Plan for Failures: No system is immune to failure, including EBS volumes. Always have a failover strategy. Use AMIs and replicate critical data across different availability zones to safeguard against EBS failures. Regular backups are a must.

• Cost and Performance: Sometimes, instance store—particularly when using temporary workloads that don’t necessitate data persistence—could offer better performance, especially for I/O-intensive tasks. However, evaluate your requirements thoroughly as EBS offers a range of storage options that might meet your needs using optimized configurations.

EBS-backed instances typically deliver a balance of affordability and speed combined with the added security of persistent storage. While instance store might be cheaper for disposable, high-throughput processes, today’s range of EBS options often caters to these needs with evolving technology and competitive pricing.