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Amazon EBS storage - overview and key features

A Deep Dive into Amazon Elastic Block Store

What is EBS in AWS?

Amazon Elastic Block Store (EBS) is a high-performance storage service provided by AWS to cater for IO-intensive workloads such as databases, file systems or video rendering. Its is a highly popular and critical service for many AWS users. This blog post aims to explain what AWS EBS is, the different types of EBS volumes available, its pricing model, durability, and the AWS EBS Container Storage Interface (CSI) driver.

What is Amazon EBS?

Amazon EBS (Elastic Block Store) is a fully managed persistent block storage service designed for use with Amazon Elastic Compute Cloud (EC2) instances. It allows users to provision storage volumes that act as virtual hard drives and attach them to EC2 instances. EBS volumes provide persistent storage, enabling data to be retained even after an EC2 instance is terminated.

 

Key features of Amazon EBS include:

  • Elasticity: EBS volumes can be dynamically resized, allowing users to increase or decrease storage capacity on the fly without interrupting the running EC2 instances.

  • Snapshots: EBS supports point-in-time snapshots, providing a reliable and efficient way to back up data, clone volumes, and restore data when needed.

  • Availability and Durability: EBS volumes are designed for high availability and data durability. Amazon replicates volumes within an Availability Zone (AZ) to safeguard against hardware failures.

Types of Amazon EBS Volumes

Amazon EBS offers a range of volume types designed to cater to different performance and cost requirements. Let's explore the additional volume types:

  • General Purpose SSD (gp2): This volume type is well-suited for a wide variety of workloads. It provides a balance of price and performance, making it a popular choice for many applications. gp2 volumes deliver a baseline level of performance with the ability to burst IOPS for short periods when needed.

  • General Purpose SSD (gp3): Introduced as an evolution of the gp2 volume type, gp3 volumes provide higher baseline performance and more price predictability. Designed for a broad range of workloads, these volumes offer a balance of price and performance. They deliver consistent baseline performance and can burst to higher levels for short periods.

  • Provisioned IOPS SSD (io1): Ideal for applications that require consistent and predictable I/O performance, io1 volumes allow users to customize the number of IOPS provisioned based on their specific needs. This volume type is suitable for high-performance database workloads that demand low-latency and high-throughput storage.

  • Provisioned IOPS SSD (io2): Building upon the capabilities of io1, io2 volumes offer even higher durability, higher IOPS-to-storage ratio, and a better price-to-performance ratio. Ideal for I/O-intensive applications such as databases. These volumes provide high and consistent performance with the ability to provision specific IOPS (input/output operations per second).

EBS Durability

AWS EBS volumes are designed for high durability. Each volume is automatically replicated within its Availability Zone to protect against hardware failures, ensuring data reliability. This replication ensures that the data remains intact and accessible even if there is a failure of an underlying component. EBS io2 volumes offer durability of 99.999% while io1, gp2 and gp3 EBS volumes offer 99.8% - 99.9% durability.

AWS EBS CSI Driver

The AWS EBS Container Storage Interface (CSI) driver is an open-source project that allows container orchestration systems like Kubernetes to manage the lifecycle of EBS volumes. The CSI driver provides a consistent way to create, attach, and mount EBS volumes to containers, enabling stateful applications to use EBS for persistent storage.

 

Key Features of the AWS EBS CSI Driver:

  • Dynamic Provisioning: Automatically provisions EBS volumes based on Persistent Volume Claims (PVCs) defined in Kubernetes.

  • Volume Snapshots: Supports creating snapshots of EBS volumes for backups and restores.

  • Volume Cloning: Allows cloning of existing EBS volumes to create new volumes with the same data.

  • Encryption: Supports encryption of EBS volumes, ensuring data security.

AWS EBS Pricing

For performance-sensitive applications that require consistent I/O performance and low latency, Provisioned IOPS SSD (io1 and io2) volumes are the recommended choice. io2 volumes, with their improved performance and durability, are especially well-suited for critical workloads and applications demanding high reliability.

General Purpose SSD (gp2 and gp3) volumes, on the other hand, are ideal for applications with varying I/O demands. With gp3's enhanced performance and cost predictability, it offers a compelling option for a broad range of workloads.

 

When choosing the right volume type, it's essential to consider the specific requirements of your applications, expected I/O patterns, and budget constraints. AWS users have the flexibility to mix and match volume types within their EC2 instances, tailoring storage solutions to match the unique needs of each application.

AWS EBS pricing is based on several factors:

  • Volume Type: Different volume types have different costs. SSD volumes (gp3 and io2) are typically more expensive than HDD volumes (st1 and sc1).

  • Provisioned Storage: The amount of storage you provision affects the cost. AWS charges on a per-GB basis.

  • IOPS Provisioned: For io2 volumes, the cost includes charges for the provisioned IOPS.

  • Data Transfer: There may be costs associated with data transfer in and out of EBS, depending on the scenario.

  • Snapshots: EBS snapshots, which are point-in-time backups, incur additional costs based on the amount of data stored.

You can see detailed Amazon EBS pricing here: https://aws.amazon.com/ebs/pricing/

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Benefits and use cases of Amazon EBS

Amazon EBS brings numerous advantages to businesses and developers alike. Some of the key benefits include:

  • Scalability: EBS volumes allow users to easily scale their storage resources as application demands grow or change, ensuring optimal performance without downtime.

  • Data Protection and Recovery: With EBS snapshots, users can create backup copies of their volumes and restore data in case of accidental data loss or system failures.

  • High Availability: By replicating EBS volumes within an AZ, AWS ensures data redundancy and availability, minimizing the risk of data loss due to hardware failures.

 

Amazon EBS is well-suited for a wide range of use cases, including but not limited to:

  • Database Storage: EBS provides reliable storage for databases, such as MySQL, PostgreSQL, and Oracle, ensuring data durability and consistency.

  • Web Hosting: Hosting websites and web applications on EC2 instances with EBS volumes ensures persistent storage for static and dynamic content.

  • Big Data Processing: EBS volumes, especially io1, are an excellent choice for processing and analyzing vast amounts of data in big data environments.

What is Amazon EBS not good for?

While Amazon EBS offers numerous benefits, it's essential to consider its downsides and limitations when using it for your applications:

  1. Limited IOPS Bursting: While General Purpose SSD (gp2 and gp3) volumes provide IOPS bursting capabilities, this burst is limited to a certain baseline level and a burst bucket. Workloads with consistently high I/O demands may experience reduced performance during prolonged burst use.

  2. Durability: 99.999% durability is available only for the most expensive volume tier (io2) and it's generally lower than durability of other high-performance block storage solutions. For example, simplyblock offers 99.9999% durability on AWS.

  3. IOPS and Throughput Provisioning Costs: Provisioned IOPS SSD (io1 and io2) volumes allow users to specify the number of IOPS provisioned for their applications. However, achieving high IOPS performance may incur additional costs, making it crucial to carefully optimize IOPS provisioning for cost efficiency.

  4. Volume Size and Performance Scaling: Resizing volumes may lead to temporary performance degradation, particularly when increasing the size of io1 and io2 volumes. It's essential to plan for volume resizing during maintenance windows to minimize potential application impacts.

  5. Single Availability Zone (AZ) Replication: By default, Amazon EBS volumes are replicated within a single Availability Zone (AZ) to ensure data durability within the same data center. While this protects against hardware failures within an AZ, it does not provide geographic redundancy.

  6. Data Transfer Costs: When using Amazon EBS volumes with Amazon EC2 instances in different AZs or regions, data transfer between instances may incur additional charges. It's crucial to consider these costs, especially for applications with high data transfer requirements.

  7. Snapshot Costs and Performance Impact: While EBS snapshots provide an efficient way to back up data, creating and managing snapshots may incur additional storage costs. Additionally, taking frequent snapshots can impact volume performance during the snapshot creation process.

  8. Backup and Restore Time: The time taken to create and restore EBS snapshots varies depending on the volume size and the amount of data being backed up or restored. Large volumes or extensive datasets may require longer backup and restore times.

  9. Network Latency: EBS volumes rely on network connectivity between EC2 instances and the underlying storage infrastructure. In situations with high network latency, application performance may be affected.

  10. Volume Attachment Limitations: Each Amazon EC2 instance has a limit on the number of Amazon EBS volumes that can be attached. This limit varies based on the instance type, and exceeding the limit may require using additional instances or managing data across multiple volumes.

  11. Lifecycle Management Complexity: As the number of EBS volumes grows, managing their lifecycle, including backups, snapshots, and resizing, can become complex and require proper monitoring and automation.

Conclusion

AWS EBS is a powerful and flexible block storage service that offers a range of volume types to meet diverse performance and cost requirements. Its high durability, along with features like snapshots and encryption, make it a reliable choice for persistent storage in the cloud. The AWS EBS CSI driver further extends its capabilities to containerized environments, making it easier to manage and scale storage for stateful applications.

By understanding the different aspects of AWS EBS, including its pricing, volume types, durability, and integration with Kubernetes through the CSI driver, you can make informed decisions to optimize your cloud storage strategy.

Simplyblock: NVMe-Optimized AWS Cloud Block Storage

Simplyblock is the NVMe-optimized software-defined cloud block storage, enabling storage requirements for the most demanding workloads on AWS. High IOPS per Gigabyte density, low predictable latency, and high throughput is enabled using the pooled storage, as well as our distributed data placement algorithm. Using erasure coding (a better RAID) instead of replicas helps to minimize storage overhead without sacrificing data safety and fault tolerance. It is designed to serve as Kubernetes Persistent Volumes for EKS though own StorageClass with simplyblock CSI driver.

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