The exam often tests whether you know when to use EC2 instance store versus Amazon EBS. The key is recognizing when ephemeral, high-performance storage is more cost-effective than persistent storage.
Quick Definition
Amazon EC2 Instance Store provides ephemeral block-level storage physically attached to the host computer. Data is lost if the instance stops, hibernates, or terminates.
Amazon EBS (Elastic Block Store) provides persistent, network-attached block storage that remains available even after instance termination.
If your data must persist after instance stop/terminate → EBS; if it can be lost → Instance Store.
Scenario
A gaming company is building a real-time video processing pipeline to render highlight reels from live-streamed matches.
The workload requires
Up to 500 GB of temporary storage for raw frames
Extremely high random IOPS (~40,000) during rendering
No data persistence once the output video is finalized
A cost-effective solution, since storage is discarded after each job
Solution – Storage-Optimized EC2 Instance with Instance Store
The team selects a storage-optimized Amazon EC2 instance that includes instance store volumes.
Instance store provides tens of thousands of low-latency random IOPS at no additional storage cost.
It’s ideal for ephemeral data — temporary files, caches, or buffers that can safely be discarded when the instance stops.
It’s more cost-effective than Provisioned IOPS EBS volumes, which would be overkill for temporary workloads.
This design balances performance and cost, making instance store the right choice for short-lived, I/O-intensive workloads.
IOPS, or Input/Output Operations Per Second, measures how many read/write operations a storage system can perform per second. When you see “temporary + very high IOPS,” think Instance Store; when you see “persistent + high IOPS,” think EBS io1/io2.)
Cheat Sheet: AWS Storage Options for Temporary vs. Persistent Data
Storage Type | Best For | Durability | Cost | Notes |
|---|---|---|---|---|
Instance Store | Temporary, high-IOPS workloads | Ephemeral (lost when instance stops) | 💲 Free with instance | Ideal for rendering, caching, scratch data |
EBS General Purpose SSD (gp3) | Balanced workloads | Persistent | 💲💲 | Good baseline choice, not ideal for very high IOPS |
EBS Provisioned IOPS (io1/io2) | Mission-critical DBs, transactional systems | Persistent | 💲💲💲 | Supports up to 64K IOPS, costly for temporary use |
Amazon S3 | Durable object storage | Highly durable (11 9s) | 💲 Low | Best for storing results/output, not scratch space |
Exam Tips
Exam Tip | Key Point | Why It Matters |
|---|---|---|
Instance Store = Ephemeral | Data disappears if instance stops | Correct for rendering, caching, scratch space |
EBS io1/io2 = High-IOPS Persistent | Expensive but durable | Correct for databases, not temporary workloads |
gp3 = Balanced | Low-latency SSD, ~16K IOPS | Good for general apps |
Match IOPS Clues | “Temporary + high IOPS” = Instance Store | Helps avoid distractors |
Exam Highlights
Instance store = best for temporary, cost-effective, high-IOPS needs.
Watch for keywords: “temporary,” “ephemeral,” “discarded after use,” “40,000+ IOPS.”
Ready to take your AWS Solutions Architect – Associate prep to the next level?
Join our Study Notes and Study Group to connect with fellow learners, access structured exam-aligned resources (study notes, flashcards, scenario-based questions, personalized study plans with email reminders, and the ability to add notes to any lesson), and participate in weekly, exam-aligned sessions using a live AWS environment to explore architecture decisions through a real-world e-commerce application.
Start your journey here: https://labs.itassist.com/aws-certified-solution-architect-associate-study-notes
📺 New to the platform? Watch the YouTube playlist to see all the features in action: https://www.youtube.com/playlist?list=PLqwTb4xwPh0e7w3iNS6I7UzAds7wNlAo7