Block storage is a crucial component when dealing with large amounts of data, and understanding its various types, including hard disk drive (HDD) and solid-state drive (SSD), can be essential for becoming an AWS Certified Solutions Architect – Associate (SAA-C03). This certification requires an in-depth knowledge of AWS services, including thoroughly grasped concepts of block storage. Amazon Elastic Block Store (EBS) is one such service, providing block storage that’s both scalable and secure, perfect for use with Amazon EC2 instances in the AWS Cloud.
1. Understanding Block Storage
Block storage can be likened to a physical hard drive in that it allows data to be stored in uniform ‘blocks’. These blocks function independently, allowing data to be spread across different volumes for distributed data storage. This distributed storage approach enhances data accessibility and makes block storage suitable for applications performing frequent read and write operations such as big data analytics or media editing and serving.
2. Hard Disk Drive (HDD) Volume Types
Amazon EBS provides two major types of HDD-backed volumes, each designed to meet specific storage needs:
- Throughput Optimized HDD (st1): Suited for large block, sequential write and read operations, perfect for big data operations, including data warehousing and log processing. The baseline performance is characterized by the size of the volume. For example, a 1TB volume has a baseline throughput of 40 MiB/s.
- Cold HDD (sc1): Optimized for large, sequential read operations, making it a cost-effective choice for less frequently accessed workloads. A 1TB volume comes with a baseline performance of 12 MiB/s.
3. Solid State Drive (SSD) Volume Types
Amazon EBS also provides SSD-backed volumes for those workloads demanding high IOPS. There are two major types of SSD volumes:
- General Purpose SSD (gp2): Default EBS volume type for general use, providing a balance of price and performance. It’s well-suited for a wide variety of transactional workloads, including development and test environments, low-latency interactive applications, and boot volumes. For example, a gp2 volume provides a baseline IOPS of 3 IOPS per GB.
- Provisioned IOPS SSD (io1 & io2): This is the highest performance SSD volume type for mission-critical, I/O intensive applications and databases. io2 volumes are the latest version, offering 99.999% durability and up to 500 IOPS/GB, which is 100x more than io1.
Below is a comparative table showing some attributes of the various EBS Volume types:
| Volume Type | Use Case | Performance | Price-Performance |
|---|---|---|---|
| st1 | Big Data, Data warehousing | High throughput | High |
| sc1 | Cold storage, infrequent access | Low throughput | Low |
| gp2 | General Purpose | Balanced | Moderate |
| io1/io2 | Critical business applications | High IOPS | High |
Remember, your choice of volume type would largely depend on the workload requirements in terms of performance, cost, and capacity. Importantly, EBS volumes are elastic, thus you can change your choice of volume type post-creation to optimize your storage cost/performance trade-off.
Understanding block storage, especially with reference to HDD and SSD volume types, can greatly aid your preparation for the AWS Certified Solutions Architect – Associate (SAA-C03) exam. We hope this article helps solidify those concepts, aiding in your understanding of AWS block storage options. Happy learning!
Practice Test
True or False: Solid State Drives (SSDs) have moving parts which makes them slower in speed.
- True
- False
Answer: False.
Explanation: Unlike Hard Disk Drives (HDDs), Solid State Drives (SSDs) have no moving parts, which allows them to access data faster.
True or False: HDD and SSD both use electrical power to store data, even when they are turned off.
- True
- False
Answer: False.
Explanation: SSDs use electrical power to store data, but HDDs use magnetic storage, which does not require power when turned off.
Which AWS storage options support the block storage feature?
- A) Amazon S3
- B) Amazon EBS
- C) Amazon Glacier
- D) DynamoDB
Answer: B) Amazon EBS
Explanation: Amazon Elastic Block Store (EBS) provides block-level storage volumes for use with Amazon EC2 instances.
True or False: Amazon EBS provides the ability to back up point-in-time snapshots of your data to Amazon S3 for durability.
- True
- False
Answer: True.
Explanation: This functionality helps protect for both single-AZ and multi-AZ database deployments.
True or False: SSDs have a higher capacity for storage than HDDs.
- True
- False
Answer: False.
Explanation: While SSDs are faster, HDDs generally have a higher storage capacity.
From the AWS EBS volume types, which one offers the lowest cost per GB?
- A) Provisioned IOPS SSD (io1)
- B) General Purpose SSD (gp2)
- C) Throughput Optimized HDD (st1)
- D) Cold HDD (sc1)
Answer: D) Cold HDD (sc1)
Explanation: Cold HDD (sc1) volumes are designed for less frequently accessed workloads.
Which AWS EBS volume type should you use for a use case that requires a high rate of random IOPS?
- A) Provisioned IOPS SSD (io1)
- B) General Purpose SSD (gp2)
- C) Throughput Optimized HDD (st1)
- D) Cold HDD (sc1)
Answer: A) Provisioned IOPS SSD (io1)
Explanation: Provisioned IOPS SSD (io1) is designed to deliver fast performance for I/O intensive workloads.
True or False: In comparison to SSDs, HDDs are more resistant to physical shock.
- True
- False
Answer: False.
Explanation: HDDs have moving parts and they can be more vulnerable to physical shock, whereas SSDs have no moving parts making them more resistant to physical shock.
True or False: File systems in a block storage are managed by the user’s operating system.
- True
- False
Answer: True.
Explanation: Block storage is used as raw storage capacity, where the user’s operating system manages the file system which includes managing the files.
What type of storage is EBS?
- A) Object storage
- B) Block storage
- C) File storage
- D) Data warehousing
Answer: B) Block storage
Explanation: EBS provides block-level storage volumes for use with EC2 instances.
True or False: You can attach multiple Amazon EBS volumes to a single instance.
- True
- False
Answer: True.
Explanation: AWS allows you to attach multiple volumes to a single instance, but each volume can be attached to only one instance at a time.
True or False: Both HDD and SSD are non-volatile memory storage.
- True
- False
Answer: True.
Explanation: Both HDD and SSD retain their data even after being powered off, which makes them non-volatile storage devices.
The main difference between SSD and HDD is:
- A) Speed
- B) Capacity
- C) Durability
- D) All of the above
Answer: D) All of the above
Explanation: SSDs are generally faster, more durable but have less capacity than HDDs.
True or False: In AWS EBS, once data is written to a provisioned IOPS SSD (io1) volume, it is automatically replicated within its availability zone to prevent data loss.
- True
- False
Answer: True.
Explanation: EBS volume data is automatically replicated within its Availability Zone which single point of failures.
True or False: For non-I/O intensive and infrequent access to your data, it is cost-effective to use HDD volumes.
- True
- False
Answer: True.
Explanation: For infrequent access and less I/O intensive use-cases, it is more cost effective to use HDD volumes as they cost less per twice.
Interview Questions
What is block storage in the context of AWS services?
Block storage in AWS refers to the Amazon Elastic Block Store (EBS) service which provides raw block-level storage that can be attached to Amazon EC2 instances.
What volume types does Amazon Elastic Block Store (EBS) offer?
Amazon EBS offers four different volume types: General Purpose SSD (gp2, gp3), Provisioned IOPS SSD (io1, io2), Throughput Optimized HDD (st1), and Cold HDD (sc1).
Which Amazon EBS volume type is best suitable for boot volumes and low-latency interactive apps?
The General Purpose SSD (gp2, gp3) volume type is best suitable for boot volumes and low-latency interactive apps.
When would you choose the Provisioned IOPS SSD (io1, io2) EBS volume type?
Provisioned IOPS SSD (io1, io2) is best suited for critical business applications that require sustained IOPS performance or more than 16,000 IOPS or 500 MiB/s of throughput per volume.
In the context of AWS EBS, when would you use Throughput Optimized HDD (st1)?
Throughput Optimized HDD (st1) is good for frequently accessed, throughput-intensive workloads with large datasets and large I/O sizes, such as MapReduce and Kafka.
What Amazon EBS volume would you choose for less frequently accessed workloads?
For infrequently accessed workloads, the Cold HDD (sc1) volume type is the most cost-effective choice.
Can you increase the size of an EBS volume after it’s created?
Yes, you can increase the size, adjust the performance, or change the volume type of your EBS volumes without stopping your instance.
How do you ensure high durability of data in Amazon EBS?
Amazon EBS replicates its data within its zone to prevent data loss due to the failure of any single hardware component.
Can ephemeral storage be used as block storage in AWS?
Yes, ephemeral storage on EC2 instances can be used as block storage, however, it is tied to the instance lifecycle and data is lost when the instance is stopped or terminated.
What EBS volume types support EBS Multi-Attach?
As of today, only io1 and io2 volumes support EBS Multi-Attach feature.
Can Amazon EBS volumes be transferred across AWS regions?
No, EBS volumes are tied to a specific region. However, you can take a snapshot and transfer the snapshot to different regions.
Can Amazon EBS volumes attached to the one EC2 instance be attached to another EC2 instance?
Yes, but you have to first detach them from the first EC2 instance before attaching them to another.
What is the AWS service that move data across your Amazon EBS volumes and Amazon S3?
This service is called Amazon EBS Snapshots. It allows you to make backups of your data and shares them across different EBS volumes and Amazon S3.
Can I encrypt my Amazon EBS volumes?
Yes, you can use AWS Key Management Service (AWS KMS) to create a key and encrypt your Amazon EBS volumes.
Can Amazon EBS snapshots be used for long-term backups?
Yes, Amazon EBS snapshots can be used for point-in-time recovery and long-term backups as they capture a state of a volume and save it to Amazon S3.
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