Elastic Block Store

Amazon Elastic Block Store (EBS) is a fundamental component of Amazon Web Services (AWS), providing scalable and highly available block-level storage volumes for EC2 instances.

It provides persistent block-level storage volumes for Amazon EC2 instances. These volumes behave as raw, unformatted block devices and can be mounted on instances. They persist independently from the instance's lifecycle and allow the creation of file systems or usage as block devices (similar to hard drives).

EBS volumes are dynamically configurable and are recommended for data requiring quick access and long-term persistence.

They are ideal for primary storage in file systems, databases, or applications needing fine-grained updates and raw block-level storage access.

EBS suits both random read/write database applications and throughput-intensive tasks involving continuous reads and writes.

Amazon EBS provides a reliable storage solution for critical workloads, ensuring data persistence, backup, and disaster recovery capabilities. Here are the key aspects of Amazon EBS:

  • Durability and Redundancy: EBS volumes automatically replicate within the same Availability Zone (AZ) to protect against component failure. For additional fault tolerance, you can create snapshots of EBS volumes and copy them across different AZs or regions.
  • Elasticity: EBS volumes can be easily resized, allowing you to adjust your storage capacity as your requirements change. This flexibility eliminates the need for over-provisioning, ensuring cost efficiency.
  • Performance: EBS provides different volume types optimized for various use cases, offering varying levels of I/O performance. From general-purpose SSD volumes to high-performance provisioned IOPS SSD volumes, EBS enables you to choose the right storage type for your applications.
  • Snapshots: EBS allows you to create point-in-time snapshots of volumes. These snapshots are incremental backups, capturing only the changed data since the last snapshot. Snapshots are stored in Amazon S3, making them highly durable and accessible across different regions.

Types of Amazon EBS Volumes

Amazon EBS offers multiple volume types, each tailored to specific use cases and performance requirements:

  • General Purpose SSD (gp2): General-purpose SSD volumes provide a balance of price and performance. They are suitable for a wide range of workloads, including small to medium-sized databases and development/test environments.
  • Provisioned IOPS SSD (io1): Provisioned IOPS SSD volumes deliver high-performance storage for I/O-intensive applications, such as large relational databases or NoSQL databases. You can provision a specific level of IOPS based on your application requirements.
  • Cold HDD (sc1): Cold HDD volumes offer low-cost storage optimized for infrequent access workloads, such as data warehouses and backup storage. While they provide lower throughput than SSD volumes, they are cost-effective for storing large amounts of data.
  • Throughput Optimized HDD (st1): Throughput Optimized HDD volumes deliver low-cost storage optimized for frequently accessed, throughput-intensive workloads. They are ideal for big data and data warehouse applications that require high throughput.
  • Magnetic (standard): Magnetic volumes, also known as standard volumes, provide the lowest cost per gigabyte of all EBS volume types. They are suitable for workloads with low I/O performance requirements, such as archival storage or development environments.

Instance Storage

Instance storage, also known as ephemeral storage, refers to the temporary block storage directly attached to an Amazon EC2 instance.

This storage is physically connected to the host machine where the instance runs.

Instance storage provides high I/O performance and low latency, making it ideal for applications requiring fast data access, such as cache storage or temporary processing.

  • Volatility: Instance storage is volatile, meaning the data stored on it is lost if the associated instance is stopped, terminated, or if the underlying hardware fails. It is intended for temporary storage and is not suitable for critical, long-term data.
  • Auto-Delete: Instance storage is automatically deleted when the associated EC2 instance is terminated, and it cannot be detached or reattached to another instance.
  • Use Cases: Instance storage is suitable for stateless applications, temporary storage of intermediate data, and high-performance computing tasks where data can be recomputed if lost.

Amazon Elastic Block Store (EBS)

Amazon EBS, on the other hand, provides persistent block-level storage volumes that can be attached to Amazon EC2 instances.

Unlike instance storage, EBS volumes are network-attached and persist independently from the life of an instance.

EBS volumes are suitable for data that requires long-term persistence, durability, and the ability to survive instance failures.

  • Durability: EBS volumes are highly durable and can be configured for replication within an Availability Zone (AZ). Snapshots of EBS volumes are stored in Amazon S3, providing additional data protection.
  • Persistence: EBS volumes persist even if the associated EC2 instance is stopped or terminated. They can be detached from one instance and attached to another, allowing data mobility.
  • Use Cases: EBS volumes are ideal for databases, file systems, application data, and any workload that requires reliable, long-term storage. They are suitable for mission-critical applications where data durability and persistence are essential.

Differences between EBS and Instance Storage

  • Durability and Persistence: EBS provides durable and persistent storage, while instance storage is volatile and temporary.
  • Data Loss: Data stored in instance storage is lost if the instance is terminated. EBS data persists even if the instance is terminated or stopped.
  • Use Cases: Instance storage is suitable for temporary, stateless applications, whereas EBS is designed for long-term data storage and applications requiring data persistence.
  • Availability: EBS volumes can be accessed from multiple instances, providing data accessibility even if one instance fails. Instance storage is specific to a single instance and cannot be shared or accessed by other instances.

In summary, Instance storage offers high-performance, temporary storage for specific use cases, while EBS provides reliable, persistent storage for a wide range of applications requiring data durability and mobility.