Concepts
Block storage is a critical component for a variety of workloads in cloud environments. It provides a way to store data in fixed-sized blocks and is typically used with database systems, file systems, and as raw storage. In the context of AWS and preparing for the AWS Certified Solutions Architect – Associate exam, it’s important to understand the block storage options provided by AWS, primarily Elastic Block Store (EBS) and its various volume types.
Amazon Elastic Block Store (EBS)
EBS provides persistent block storage volumes for use with Amazon EC2 instances. EBS volumes are highly available and reliable and can be mirrored across multiple servers in an Availability Zone. They offer the consistency and low-latency needed for workloads that require a database, a file system, or access to raw block-level storage.
EBS volumes come in several types, each designed to cater to specific use cases:
- General Purpose SSD (gp2 and gp3)
- gp2: This is a general-purpose volume that balances price and performance for a wide variety of workloads. It is backed by Solid-State Drives (SSDs) and is a good choice for boot volumes, medium-size single-instance databases, and development and test environments.
- gp3: Introduced as an enhancement to gp2, gp3 volumes offer better performance at a lower cost and are ideal for applications that require high IOPS, throughput, or cost-effectiveness.
- Provisioned IOPS SSD (io1 and io2)
- io1: These are designed for I/O intensive workloads, particularly databases, that require sustained IOPS performance or more than 16,000 IOPS or 250 MB/s of throughout per volume.
- io2: As an advancement of io1, io2 offers higher durability, more IOPS, and is designed for business-critical applications that require high availability.
- Throughput Optimized HDD (st1)
- st1: These are low-cost HDD volumes designed for frequently accessed, throughput-intensive workloads and are perfect for data warehouses and big data processing.
- Cold HDD (sc1)
- sc1: These are the lowest-cost HDD volumes and are designed for less-frequently accessed workloads, such as file servers.
- Magnetic
- Older generation HDD that is rarely used now for new volumes, suitable for workloads where data is infrequently accessed.
When choosing an EBS volume type for your use case, it is crucial to consider factors such as performance (IOPS/throughput), latency, the size of volumes, and cost-efficiency. Here is a simplified comparison of the most popular SSD-based EBS volume types:
| Volume Type | Use Case | Max IOPS | Max Throughput | Durability | Cost |
|---|---|---|---|---|---|
| gp2 | General purpose | 3,000-16,000 IOPS | 250 MB/s | 99.8%-99.9% | Medium |
| gp3 | General purpose, higher performance | 16,000 IOPS | 1,000 MB/s | 99.8%-99.9% | Low |
| io1 | High-intensity I/O | 64,000 IOPS | 1,000 MB/s | 99.8%-99.9% | High |
| io2 | Business-critical applications | 64,000-256,000 IOPS | 1,000 MB/s | 99.999% (higher durability) | Very High |
Note: The above figures are examples and AWS constantly updates its offerings; please refer to the current AWS documentation for the latest details.
In addition to selecting the right volume type, you should also be familiar with other features of EBS such as snapshotting, which allows you to take backups of your volumes, enabling point-in-time recovery, and encryption for securing data both at rest and in transit.
For practice and understanding, let’s look at how you would create a new gp3 volume and attach it to an existing EC2 instance using AWS CLI:
# Create a new gp3 volume
aws ec2 create-volume –availability-zone us-west-2a –size 80 –volume-type gp3 –tag-specifications ‘ResourceType=volume,Tags=[{Key=Name,Value=MySampleVolume}]’
# Take note of the VolumeId in the output, and then attach it to an existing EC2 instance with the instance ID i-1234567890abcdef0:
aws ec2 attach-volume –volume-id vol-049df61146fXXXXX –instance-id i-1234567890abcdef0 –device /dev/sdf
Understanding these options and how to deploy them is crucial for designing robust, cost-effective, and high-performance AWS environments, which is an important aspect of the AWS Certified Solutions Architect – Associate exam.
Answer the Questions in Comment Section
True or False: Block storage can be mounted by more than one instance at the same time.
- True
- False
Answer: False
Explanation: Block storage is typically a single-instance storage, meaning that it can only be attached to one server or instance at a time. To share storage, file storage or object storage services are more suitable.
In AWS, what is the block storage service called?
- Amazon S3
- Amazon EBS
- Amazon EFS
- Amazon Glacier
Answer: Amazon EBS
Explanation: Amazon Elastic Block Store (Amazon EBS) is the block storage service designed for use with Amazon EC2 instances for both throughput and transaction-intensive workloads at any scale.
Which AWS volume type offers the highest IOPS performance?
- General Purpose SSD (gp2)
- Provisioned IOPS SSD (io1/io2)
- Throughput Optimized HDD (st1)
- Cold HDD (sc1)
Answer: Provisioned IOPS SSD (io1/io2)
Explanation: Provisioned IOPS SSD (io1/io2) are the highest-performance EBS storage options designed for I/O-intensive applications, offering the highest IOPS and throughput.
What does the SSD in SSD volume types stand for?
- Secure Storage Disk
- Solid State Drive
- Single Storage Drive
- Synchronized System Disk
Answer: Solid State Drive
Explanation: SSD stands for Solid State Drive, which is a type of storage device that uses integrated circuit assemblies to store data persistently, and it is known for faster access times compared to HDDs.
True or False: HDD-based volumes are preferred over SSD-based volumes for latency-sensitive transactional workloads.
- True
- False
Answer: False
Explanation: SSD-based volumes are preferred over HDD-based volumes for transactional workloads where low latency is required. HDD-based volumes are typically used for throughput-intensive workloads.
Which of the following is a characteristic of Cold HDD (sc1) volumes in AWS?
- High IOPS
- Lowest cost HDD volume designed for infrequent access
- High throughput performance
- Suitable for frequently accessed data
Answer: Lowest cost HDD volume designed for infrequent access
Explanation: Cold HDD (sc1) volumes are designed for infrequent access and are the lowest cost hard disk drive (HDD) volume provided by AWS.
True or False: Amazon EBS Provisioned IOPS (PIOPS) are designed to deliver a consistent IOPS rate, even under high load.
- True
- False
Answer: True
Explanation: Provisioned IOPS (PIOPS) are designed to deliver consistent IOPS performance, and users can specify an IOPS rate when creating the volume to meet the performance requirements of their application.
In AWS EBS, what is the purpose of snapshotting?
- To increase volume size
- To create a point-in-time copy of a volume
- To transfer volumes between Availability Zones
- To change volume types
Answer: To create a point-in-time copy of a volume
Explanation: Snapshotting in AWS EBS is used to create a point-in-time copy of a volume, which can be used for backups or to create new volumes.
True or False: It is possible to increase the size of an EBS volume without stopping the attached EC2 instance.
- True
- False
Answer: True
Explanation: It is possible to modify the size, performance, or type of an EBS volume without disrupting the attached EC2 instance, allowing for greater flexibility and dynamic scaling of resources.
Which AWS EBS volume type is best suited for big data and data warehousing workloads?
- General Purpose SSD (gp2)
- Provisioned IOPS SSD (io1/io2)
- Throughput Optimized HDD (st1)
- Cold HDD (sc1)
Answer: Throughput Optimized HDD (st1)
Explanation: Throughput Optimized HDD (st1) volumes are HDD volumes intended for throughput-intensive workloads and are particularly well-suited for big data and data warehousing workloads.
An EBS volume remains in the same Availability Zone as the EC2 instance it is attached to. True or False?
- True
- False
Answer: True
Explanation: An EBS volume is always in the same Availability Zone as the EC2 instance it’s attached to because it provides block level storage that is only accessible within the same AZ for low-latency interaction.
EBS volumes support both sequential and random I/O access. True or False?
- True
- False
Answer: True
Explanation: EBS volumes are designed to support diverse workloads and support both sequential (such as log processing) and random I/O access patterns (such as databases).
Great post! I’ve been trying to understand the differences between HDD and SSD volume types for the SAA-C03 exam.
Can anyone explain if there’s a significant cost difference between using HDD and SSD in Amazon EBS?
For those who are prepping for the AWS Certified Solutions Architect exam, remember that SSD volumes are better for mission-critical applications where performance is key.
I’m having trouble deciding between gp2 and gp3 volume types. Any advice?
Thanks! This post clarified a lot for me.
One key point to remember is that HDD volumes are limited by IOPS, making them less suitable for high-performance applications.
Appreciate the detailed breakdown of storage options!
It’s crucial to match your storage type with your workload requirements. Over-provisioning can lead to unnecessary costs.