Concepts
They allow users to store data in volumes that can be attached to cloud instances, providing persistent and high-performance storage. Two common block storage solutions provided by Amazon Web Services (AWS) are Amazon Elastic Block Store (Amazon EBS) and instance store, which are often part of the AWS Certified Cloud Practitioner exam’s curriculum.
Amazon Elastic Block Store (Amazon EBS)
Amazon EBS provides block level storage volumes for use with EC2 instances. EBS volumes behave like raw, unformatted block devices that can be attached to AWS instances. The main features of Amazon EBS include:
- Persistence: EBS volumes persist independently of the life of an instance.
- Performance: Offers a range of volume types tailored to different use cases, such as general-purpose (gp2, gp3), provisioned IOPS (io1, io2), and throughput-optimized (st1) or cold (sc1) hard disk drive volumes.
- Data Availability and Reliability: EBS volumes are automatically replicated within the same Availability Zone (AZ) to prevent data loss due to failure of any single hardware component.
- Encryption: EBS volumes can be encrypted to protect data at rest, and the data in transit between the volume and the instance can also be encrypted using the Amazon EBS encryption feature.
- Snapshots: Create point-in-time snapshots of volumes, which are backed up to Amazon S3 and can be used to create new EBS volumes.
- Scalability: Easily increase volume size, change volume type, or adjust performance characteristics.
Here is a simplified example scenario using EBS:
An admin attaches a 500 GB EBS volume to a running instance to host a database that requires high IOPS. They select the io2 volume type due to its higher durability and provisioned IOPS feature, ensuring consistent performance for transactional workloads.
Instance Store
An instance store provides temporary block-level storage for an Amazon EC2 instance. This storage is physically attached to the host computer that is running the instance. The primary characteristics of instance store volumes include:
- Temporary Storage: Instance store volumes exist only for the life of the associated instance. If the instance is stopped, terminated, or fails, the data on instance store volumes is lost.
- Performance: Instance store volumes can provide very high I/O performance because they are physically attached to the host machine, but their performance can vary depending on the instance type.
- Use Cases: Instance stores are ideal for temporary storage of information that changes frequently, such as buffers, caches, scratch data, and other temporary content.
An illustrative example of using instance store is:
A temporary cache for a large-scale web application can be deployed using instance store to ensure very high I/O performance. However, it’s critical to design the system with redundancy in mind since data on instance store volumes will be lost if the instance is stopped or fails.
Comparison
| Feature | Amazon EBS | Instance Store |
|---|---|---|
| Lifetime | Independent | Instance lifetime |
| Data Durability | High (with backups) | Low (ephemeral) |
| Performance | High, different types available | High, varies with instance |
| Encryption | Available | Not available |
| Snapshots | Yes | No |
| Scalability | Yes | No |
| API Access | Fully supported | Actions via EC2 API |
In summary, when preparing for the AWS Certified Cloud Practitioner exam, it’s important to understand the differences between Amazon EBS and instance store, as well as the scenarios in which each is most effective. Amazon EBS is suited for durable, persistent, and scalable storage solutions, whereas instance store is ideal for temporary storage with potentially higher I/O performance but less durability and permanence.
Answer the Questions in Comment Section
True or False: Amazon EBS volumes can only be attached to one instance at a time.
- True
- False
Answer: True
Explanation: Amazon EBS volumes are designed to be attached to a single instance at a time; however, EBS Multi-Attach enables you to attach a Provisioned IOPS SSD (io1 and io2) volumes to up to 16 Nitro-based instances in the same Availability Zone.
Instance store volumes persist independently of the life of the EC2 instance to which they are attached.
- True
- False
Answer: False
Explanation: Instance store volumes are ephemeral storage that exists only during the life of the EC2 instance. If the instance is stopped, terminated, or fails, the data is lost.
Which of the following Amazon EBS volume types is backed by solid-state drives (SSDs)?
- Provisioned IOPS SSD
- Throughput Optimized HDD
- Cold HDD
- Magnetic
Answer: Provisioned IOPS SSD
Explanation: Provisioned IOPS SSD is an EBS volume type that is backed by SSDs and is designed to handle I/O-intensive workloads.
Amazon EBS volumes are automatically encrypted.
- True
- False
Answer: False
Explanation: Amazon EBS volumes are not encrypted by default. You have the option to enable encryption when you create the volume or you can encrypt an existing volume using AWS services such as EBS snapshots and AWS Key Management Service (KMS).
What feature allows EBS volumes to be automatically replicated within their Availability Zone to protect from component failure?
- Multi-AZ deployments
- EBS Snapshots
- EBS volume mirroring
- EBS volume redundancy
Answer: EBS volume redundancy
Explanation: Amazon EBS provides automatic replication within the Availability Zone for protection against component failure, offering high availability and durability.
Amazon EBS provides which of the following benefits? (Select TWO)
- Increased compute capacity for EC2 instances
- Persistent block storage volumes for EC2 instances
- Consistently low-latency performance
- Temporary storage for batch processing jobs
- Automatically scaling storage capacity
Answer: Persistent block storage volumes for EC2 instances, Consistently low-latency performance
Explanation: Amazon EBS provides persistent block storage volumes for EC2 instances with consistently low-latency performance. EBS is not for temporary storage or automatic scaling of storage capacity.
True or False: You can take a point-in-time snapshot of an Instance Store volume.
- True
- False
Answer: False
Explanation: Instance Store volumes cannot be snapshotted. Snapshots can only be taken of EBS volumes.
Which Amazon EBS volume type offers the lowest cost per gigabyte?
- Provisioned IOPS SSD (io2)
- General Purpose SSD (gp3)
- Throughput Optimized HDD (st1)
- Cold HDD (sc1)
Answer: Cold HDD (sc1)
Explanation: Cold HDD (sc1) volumes are designed for less frequently accessed workloads and offer the lowest cost per gigabyte of all EBS volume types.
Instance store volumes provide higher IOPS than EBS Provisioned IOPS SSD volumes.
- True
- False
Answer: False
Explanation: Instance store volumes can provide high IOPS, but EBS Provisioned IOPS SSD volumes are specifically designed to offer higher and more consistent IOPS performance for I/O-intensive applications.
True or False: Amazon EBS volumes can only be used with Amazon EC2 instances.
- True
- False
Answer: True
Explanation: Amazon EBS volumes are designed to be used with EC2 instances, providing persistent block storage.
The maximum volume size of an EBS General Purpose SSD (gp3) volume is:
- 1 TB
- 16 TB
- 32 TB
- 64 TB
Answer: 16 TB
Explanation: As of the knowledge cutoff in 2023, the maximum volume size for an Amazon EBS General Purpose SSD (gp3) volume is 16 TB.
True or False: You can share a single Amazon EBS volume between multiple AWS accounts.
- True
- False
Answer: False
Explanation: An Amazon EBS volume is tied to a single AWS account and can only be attached to instances within the same account. However, you can create snapshots of an EBS volume and share these with other AWS accounts.
Great post, really helped me understand the different block storage solutions!
Can someone explain the key differences between Amazon EBS and instance store?
Just passed my AWS Certified Cloud Practitioner exam thanks to this tutorial!
How does the performance compare between Amazon EBS and instance store?
Great blog post on identifying block storage solutions! It really helped me understand Amazon EBS better.
What’s the main difference between Amazon EBS and instance storage?
I personally find Amazon EBS more versatile than instance stores.
Thanks for this, I was confused about the storage types for my upcoming CLF-C02 exam.