AWS 7.1 Amazon EBS Block Storage

Question 1

What is Amazon EBS and what type of storage does it provide?

Answer 1

Amazon EBS provides persistent block storage for EC2 instances.

Question 2

What does “block storage” mean in EBS?

Answer 2

Data is stored in fixed-size blocks, allowing direct access and modification of specific parts of a file.

Question 3

Explain the key difference between block storage and object storage using an example.

Answer 3

Block storage → change 1 character = update only that block
Object storage → change 1 character = rewrite entire file

Question 4

Why is block storage more efficient than object storage for certain workloads?

Answer 4

Because only the modified blocks need to be updated, instead of rewriting the entire file.

Question 5

Why is EBS considered high performance?

Answer 5

Because it provides:
* Low latency
* High throughput
* Direct attachment to EC2

Question 6

What does it mean that EBS volumes are persistent?

Answer 6

Data remains even if the EC2 instance is stopped or restarted.

Question 7

How does AWS ensure durability of EBS volumes?

Answer 7

By automatically replicating data within an Availability Zone.

Question 8

Can EBS volumes be attached to multiple instances simultaneously?

Answer 8

Typically no (standard EBS), they are attached to one instance at a time.

Question 9

What is a snapshot in EBS?

Answer 9

A backup of an EBS volume stored in Amazon S3.

Question 10

What is the baseline snapshot?

Answer 10

The first full snapshot of a volume.

Question 11

How do subsequent snapshots differ from the baseline snapshot?

Answer 11

They are incremental, storing only the changes since the last snapshot.

Question 12

Why are incremental snapshots more efficient?

Answer 12

Because they reduce:
* Storage cost
* Backup time

Question 13

What can you do with an EBS snapshot?

Answer 13

Restore volumes
* Create new volumes
* Copy across regions
* Share with other accounts

Question 14

Why are snapshots important for disaster recovery?

Answer 14

They allow data to be restored quickly in another region.

Question 15

What are the main EBS volume types?

Answer 15

• SSD (gp, io)
• HDD (st, sc)

Question 16

Which EBS volume type is best for high-performance workloads?

Answer 16

Provisioned IOPS SSD

Question 17

Which EBS type is suitable for general-purpose workloads?

Answer 17

General Purpose SSD

Question 18

Which workloads are HDD-based EBS volumes suited for?

Answer 18

Large sequential workloads
* Big data
* Data warehousing

Question 19

What is IOPS in EBS?

Answer 19

Input/Output Operations Per Second — a measure of storage performance.

Question 20

How is SSD pricing in EBS calculated?

Answer 20

Based on:
* Storage provisioned (GB/month)
* IOPS (if provisioned)

Question 21

How is HDD-based EBS pricing calculated?

Answer 21

Based on:
* Throughput
* Number of requests

Question 22

What is the cost implication of provisioned storage?

Answer 22

You pay for allocated storage, even if unused.

Question 23

What happens if you increase EBS volume size?

Answer 23

Capacity increases and cost increases accordingly.

Question 24

Can EBS volumes be resized without stopping instances?

Answer 24

Yes, they can be resized dynamically.

Question 25

What is data transfer cost in EBS?

Answer 25

Charges may apply when data is transferred between regions.

Question 26

Are snapshot storage costs free?

Answer 26

No, you are charged based on data stored in snapshots.

Question 27

Why is EBS preferred for databases?

Answer 27

Because of: * Low latency * High performance * Persistent storage

Question 28

A database requires fast, consistent performance. Which EBS type should be used?

Answer 28

Provisioned IOPS SSD

Question 29

A company needs cheap storage for large log files. Best option?

Answer 29

HDD-based EBS

Question 30

A company wants to reduce storage costs but still maintain backups. What should they do?

Answer 30

Use incremental snapshots instead of full backups

Question 31

If an EC2 instance is terminated, what happens to attached EBS volumes?

Answer 31

By default: * Root volume → deleted * Additional volumes → remain (unless configured otherwise)

Question 32

Explain how EBS supports scalability and flexibility in cloud storage.

Answer 32

* Volumes can be resized * Snapshots allow replication and recovery * Multiple volume types for different workloads