Exploring EC2 Instance Storage: Understand Your Options
Tags: aws, ec2, cloudstorage, cloudpractitioner
Published: 2023-07-26 14:16:10

When you have conversations about virtual machines like Amazon EC2 instances, it immediately becomes evident that storage plays a pivotal role in their functionality and overall performance. Storage serves as the bedrock for housing the data, files, configurations, and even the applications themselves that are essential for these computing entities to fulfil their tasks effectively. In the context of EC2 instances, storage acts as the repository for application code, database files, media assets, and various other resources required to serve users and handle data processing. Carefully choosing the right storage options for your EC2 instances ensures smooth application functioning, scalability, and accessibility, enabling seamless interactions between clients and servers. In addition, an efficient storage solution optimizes data retrieval and enhances response times, critical for delivering exceptional user experiences. The purpose of this article is to outline and explore in detail the various storage options available for EC2 instances. As always, fasten your proverbial seatbelt and go on this "EC2 instance storage options" ride with me.

## Elastic Block Storage (EBS) Volumes
Amazon EBS is a crucial and versatile storage service providing persistent block-level storage volumes for EC2 instances. It offers durable and scalable storage solutions, allowing users to create and attach storage volumes to EC2 instances seamlessly. The key advantage of EBS is its persistence, meaning that data stored on EBS volumes remains intact even after an EC2 instance is stopped or terminated, ensuring data durability and continuity. Additionally, EBS volumes can be easily detached from one EC2 instance and attached to another, facilitating data migration and application scaling without data loss. With features like EBS snapshots (more on this later), users can create point-in-time backups of volumes and restore data efficiently, enhancing data protection and enabling disaster recovery strategies. As a fundamental component in many AWS architectures, Amazon EBS ensures the reliable and scalable storage required to power applications and workloads running on EC2 instances.

EBS offers various volume types to cater to diverse workload requirements:

### General Purpose SSD (gp2)
General Purpose SSD (gp2) is a versatile and cost-effective volume type designed to provide a balance of price and performance for a wide range of workloads in the AWS ecosystem. It offers a baseline performance of 3 IOPS (Input/Output Operations Per Second) per GB with the ability to burst beyond the baseline to handle occasional spikes in workload demands. This burst capability makes gp2 volumes well-suited for applications with intermittent or variable I/O requirements. The performance of gp2 volumes is directly related to the size of the volume. Volumes up to 1 TB in size can burst up to 3,000 IOPS, and for larger volumes, the burst performance increases linearly with the volume size, up to a maximum of 16,000 IOPS. This scalability ensures that users can adjust the storage performance to meet their specific application needs, making gp2 volumes an excellent choice for workloads with fluctuating I/O patterns.

A scenario where using the gp2 EBS volume type would be a good choice is in hosting web servers or running small to medium-sized databases. In these cases, the burst capability of gp2 volumes allows them to handle traffic spikes during peak usage hours, providing responsive and consistent performance. The baseline IOPS, combined with the ability to burst beyond that, ensures that the storage can handle variable workloads without incurring additional costs for provisioning higher performance volumes. Additionally, gp2 volumes are well-suited for development and test environments, where performance requirements may vary over time. The flexibility to adjust volume size and IOPS independently allows developers to optimize storage resources based on project needs, making gp2 volumes a cost-efficient and dynamic choice for temporary workloads. Overall, the gp2 EBS volume type is an ideal option for a wide range of workloads that require cost-effective and scalable storage with burst capabilities. Its ability to accommodate both baseline and burst performance levels makes it an attractive choice for applications with varying I/O demands, providing a versatile and reliable storage solution within the AWS infrastructure.

### Provisioned IOPS SSD (io1)
The Provisioned IOPS SSD (io1) is a high-performance volume type designed to deliver predictable and consistent I/O performance for critical workloads in the AWS environment. It is purposely built for applications that require low-latency and high-throughput storage, making it an ideal choice for demanding database workloads, transactional applications, and mission-critical systems. The key feature of io1 volumes is the ability to provision a specific number of IOPS, allowing users to allocate dedicated I/O operations per second to meet stringent performance requirements. Unlike General Purpose SSD (gp2) volumes, io1 volumes do not rely on burst performance but provide a fixed number of provisioned IOPS, ensuring predictable and steady performance under any workload conditions. Io1 volumes are available in sizes ranging from 4GB to 16TB and can support up to 64,000 provisioned IOPS per volume. This level of scalability allows users to tailor the performance and capacity of their storage to the precise needs of their application, ensuring optimal performance and cost-efficiency.

A scenario where using io1 EBS volume would be a good choice is in hosting high-performance databases, such as Oracle, SQL Server, or high-transactional NoSQL databases like MongoDB or Cassandra. These databases often require low latency and consistent I/O performance to handle complex queries and large numbers of transactions. By provisioning a specific number of IOPS, io1 volumes guarantee that these databases receive the necessary I/O resources to operate efficiently, maintaining responsive performance for users and reducing the risk of performance degradation during peak usage. Also, applications with stringent Service Level Agreements (SLAs) or those processing real-time data, such as financial trading platforms or analytics systems, can greatly benefit from the predictable and reliable performance offered by io1 volumes. By tailoring the provisioned IOPS to meet the exact requirements of the workload, organizations can ensure the highest level of application responsiveness and reduce the risk of potential bottlenecks during data-intensive operations.

### Throughput Optimized HDD (st1)
The Throughput Optimized HDD (st1) volume type is specifically designed to deliver high throughput and cost-effective storage for frequently accessed, large, sequential workloads. It is an excellent choice for applications that require streaming large amounts of data, like log processing, big data analytics, or data warehousing. The key feature of st1 volumes is their ability to deliver high throughput at low cost. These volumes are optimized for large, sequential I/O operations, making them ideal for workloads that require sustained read and write performance. They offer a baseline throughput of 40 MB/s per TB and can burst to higher throughput based on volume size, up to a maximum of 500 MB/s per volume. This predictable and cost-effective performance allows users to handle data-intensive workloads without the need for provisioning costly high-performance volumes.

A scenario where using the Throughput Optimized HDD (st1) EBS volume would be a good fit is in data warehousing environments, where large datasets need to be frequently read and processed. In such scenarios, the high throughput of st1 volumes ensures efficient data ingestion and processing, optimizing the performance of data warehouse queries and analytics. Moreover, st1 volumes are suitable for applications with large-scale log processing, where sequential access to data is predominant. The high throughput and cost-effectiveness of st1 volumes make them well-suited for handling vast amounts of log data efficiently. However, for applications with random I/O patterns or workloads with frequent, small-sized read/write operations, the General Purpose SSD (gp2) volume would be a better fit. The gp2 volume's ability to burst IOPS and its lower latency make it more suitable for handling varied and unpredictable workloads, providing responsive storage performance for transactional databases, boot volumes, and web applications.

### Cold HDD (sc1)
The Cold HDD (sc1) volume type is designed for infrequently accessed, large, sequential workloads that require high-capacity storage at a lower cost. It is ideal for use cases with large data sets or backups that do not require frequent access but need to be stored cost-effectively. The key feature of sc1 volumes is their cost-effectiveness, making them suitable for workloads with low I/O requirements that prioritize storage capacity over performance. They offer a baseline throughput of 12 MB/s per TB and can burst to higher throughput based on volume size, up to a maximum of 250 MB/s per volume. The focus of sc1 volumes is on providing economical storage, making them an excellent choice for archiving data, storing backups, or long-term data retention.

It's important to keep in mind that sc1 volumes are not optimized for frequent read and write operations or random I/O patterns, and they may not be well-suited for latency-sensitive applications or transactional workloads. However, for scenarios where data access is infrequent and large capacity is paramount, such as storing historical records, log archives, or regulatory compliance data, the Cold HDD (sc1) EBS volume type offers a cost-effective solution to meet those specific storage needs. On the other hand, if the workload requires a more balanced performance that includes both storage capacity and responsive I/O operations, the General Purpose SSD (gp2) EBS volume might be a better fit. The gp2 volume provides a baseline of 3 IOPS per GB and can burst IOPS for applications with varied or unpredictable workloads. It is ideal for hosting boot volumes, small to medium-sized databases, or web applications where both storage capacity and moderate performance are essential. Thus, for workloads that require a combination of cost-effectiveness and responsive I/O, the General Purpose SSD (gp2) EBS volume would be a more suitable choice.

### Magnetic (standard)
The Magnetic (standard) is an older generation volume type designed to provide cost-effective storage for workloads with light I/O requirements. It offers a lower cost per gigabyte compared to other EBS volume types but provides lower performance characteristics. Magnetic volumes are most suitable for applications with infrequent access to data, such as small websites, test environments, or development instances. The key feature of Magnetic volumes is their cost-effectiveness, making them an economical choice for scenarios where performance is not a critical factor. They offer a baseline throughput of 40-90 IOPS per volume, which is significantly lower than other EBS volume types. Magnetic volumes are well-suited for use cases where the primary focus is on reducing storage costs while accommodating light workloads.

A scenario where using the Magnetic (standard) EBS volume would be a good choice is in setting up temporary development and testing environments. These environments often experience sporadic I/O activity, and performance is not a top priority. By using Magnetic volumes, organizations can save on storage costs without compromising the ability to create temporary instances for development and testing purposes. However, it's essential to consider the workload's requirements and the performance needs of applications before choosing Magnetic volumes. For production workloads or applications with higher I/O demands, such as databases or web servers with regular traffic, selecting higher-performance EBS volume types like gp2 or io1 would be more appropriate. In summary, Magnetic (standard) EBS volumes are an economical option for workloads with light I/O demands, such as temporary development and testing environments or small websites with infrequent data access.

After having talked about the various EBS volume types, let's go on to talk about EBS snapshots and what they entail.

## EBS Snapshot
EBS snapshots allow users to create point-in-time backups of their EBS volumes. These snapshots capture the entire state of an EBS volume, including data, configurations, and settings, at the moment the snapshot is taken. EBS snapshots are stored in Amazon Simple Storage Service (S3), providing durability and enabling easy data recovery.

They offer an efficient way to back up data on AWS. Users can create snapshots manually or schedule them periodically to ensure data is protected against accidental deletions, hardware failures, or other issues. The snapshots are incremental, meaning they only store changes made since the last snapshot. This approach reduces storage costs and optimizes backup efficiency by avoiding redundant data storage. Additionally, users can enhance data security by encrypting EBS snapshots using AWS Key Management Service (KMS) keys, ensuring that sensitive data remains protected even when stored in S3.

One of the significant benefits of EBS snapshots is their ability to restore data or create new EBS volumes in case of data loss or system failures. By restoring from a snapshot, users can quickly recover their data and resume normal operations. EBS snapshots also offer cross-region replication, enabling users to copy snapshots across AWS regions for disaster recovery and data redundancy. To streamline snapshot management, AWS provides lifecycle policies, allowing users to define rules for snapshot creation and deletion based on specific criteria. By leveraging EBS snapshots effectively, users can ensure data durability, compliance, and seamless data recovery, enhancing the reliability and resilience of their applications and infrastructure in the cloud.

## EBS Multi-Attach
EBS Multi-Attach allows multiple EC2 instances to concurrently attach to a single EBS volume. This feature is particularly useful for applications that require shared access to a common dataset, enabling higher availability and fault tolerance. By attaching a single EBS volume to multiple EC2 instances in the same Availability Zone, you create a shared storage resource that can improve application availability and resiliency. In the event of an EC2 instance failure, other instances can continue accessing the EBS volume without interruption, ensuring continuous data availability.

However, it's important to note that EBS Multi-Attach doesn't automatically handle data synchronization between instances. Applications using Multi-Attach must implement their own mechanisms for maintaining data consistency and coherency, especially when multiple instances write to the same data on the shared volume. Managing concurrent access to shared data becomes a crucial consideration to maintain data integrity. Another important aspect is performance consideration; while EBS Multi-Attach allows multiple instances to access the same volume, the overall IOPS performance remains the same as if the volume were attached to a single instance. As such, designing applications with optimized data access patterns and efficient data handling becomes essential to avoid performance bottlenecks.

In addition to EBS volumes (the persistent storage of EC2 instances), EC2 instances also have instance store volumes that serve as ephemeral storage. Let's dive into it too.

## Instance Stores
Amazon EC2 instance stores, also known as instance storage or ephemeral storage, are local, temporary storage options that come with certain EC2 instance types. Unlike EBS volumes, instance stores are physically attached to the host server where the EC2 instance is running. They provide high-performance, low-latency storage that is ideal for temporary data, caching, and scratch space.

Instance stores offer high I/O performance and low-latency access since they are directly attached to the physical hardware of the EC2 instance. This makes them well-suited for workloads that require fast and efficient data processing. However, it's important to note that instance stores are temporary and are only available for the duration of the EC2 instance's life. When the instance is stopped or terminated, the data stored in the instance store is lost. Therefore, it is essential to use instance stores for transient data that do not require persistent storage. The size and type of instance store vary based on the EC2 instance type. Some instance types have local NVMe-based SSDs, while others have HDDs or older-generation SSDs. The available instance store size ranges from tens of gigabytes to multiple terabytes.

For longer-term storage of data, AWS offers storage services such as EFS and Amazon S3. I won't be going into those in the wake of trying to make this article as EC2-centric as possible and not too lengthy.

## Final Thoughts
Understanding the various EC2 instance storage options available to you is very important in architecting robust and performant solutions on AWS. Each storage type comes with its unique set of advantages and use cases, allowing developers and system administrators to tailor their choices based on specific application requirements. EBS volumes provide reliable and durable block-level storage, with options like General Purpose SSD, Provisioned IOPS SSD, Throughput Optimized HDD, and Cold HDD catering to diverse workloads. Additionally, the ephemeral instance stores offer high-performance, temporary storage ideal for transient data and caching purposes. As you embark on or continue your cloud journey, remember that selecting the most suitable storage option is an artful blend of technical expertise and a deep understanding of your application's unique demands. So don't stop exploring the diverse EC2 instance storage landscape.