What is EC2 Instance Store?
A hardware disk physically attached to the server hosting your EC2 instance. Provides the highest possible I/O performance.
Data is lost when the instance is stopped, terminated, or the underlying hardware fails. Not for durable storage.
EBS vs Instance Store
| Feature | EBS | Instance Store |
|---|---|---|
| Connection | Network | Physical hardware |
| Performance | Up to 64K IOPS (io2) | Up to 3.3 million IOPS |
| Persistence | Survives stop/terminate | Lost on stop/terminate |
| Backup | Snapshots | Your responsibility |
| Use case | Databases, OS | Cache, buffer, temp data |
EBS vs Instance Store
Performance Example
Instance Store (i3 family):
├── Read IOPS: up to 3,300,000
└── Write IOPS: up to 1,400,000
EBS gp2:
├── Max IOPS: 16,000
└── (200x less than instance store!)
Use Cases
- ✅ Buffer / cache
- ✅ Scratch data / temporary content
- ✅ High-performance temporary storage
- ❌ Long-term storage (use EBS)
- ❌ Data that must survive instance stop
Anytime you see very high performance hardware-attached volume for EC2, think EC2 Instance Store.
Questions & Answers
Q1: What is EC2 Instance Store?
Answer:
A physical hard drive attached to the server hosting your EC2 instance. It provides the highest I/O performance available but is ephemeral — data is lost when the instance stops or terminates.
Q2: What happens to Instance Store data when you stop an EC2 instance?
Answer:
The data is completely lost. Instance Store is ephemeral storage. If you need persistent data, use EBS volumes instead.
Q3: When should you use Instance Store over EBS?
Answer:
When you need extremely high I/O performance for temporary data: buffers, caches, scratch data, or temporary content. Instance Store can deliver millions of IOPS vs EBS's thousands.
Q4: How much faster is Instance Store compared to EBS?
Answer:
Instance Store (i3 family) can reach 3.3 million read IOPS, while EBS gp2 maxes out at 16,000 IOPS. That's roughly 200x more performance.
Q5: Who is responsible for backing up Instance Store data?
Answer:
You are. AWS does not back up Instance Store data. If you use it, you must implement your own backup and replication strategy.
Q6: What happens if the underlying server hardware fails?
Answer:
You lose all data on the Instance Store because the physical disk is attached to that specific server. This is another reason it's called ephemeral storage.
Q7: Can all EC2 instance types use Instance Store?
Answer:
No. Only specific instance types (like i3, d2, h1) come with Instance Store volumes. The availability depends on the instance family.
Q8: Can you detach an Instance Store volume and attach it to another instance?
Answer:
No. Instance Store is physically attached to the host server. It cannot be detached or moved. Only EBS volumes (network drives) can be detached and reattached.
Q9: Is Instance Store included in the EBS free tier?
Answer:
No. Instance Store is not an EBS product. It's part of the EC2 instance itself. The cost is included in the EC2 instance pricing for instance types that support it.
Q10: What is the exam keyword for Instance Store?
Answer:
Look for: very high performance, hardware-attached, millions of IOPS, ephemeral, temporary storage. Any of these should make you think EC2 Instance Store.
Check yourself
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