As part of my preparation for the AWS SysOps Administrator certification exam, I’ve been studying Amazon Elastic Block Store (EBS), a core storage service in AWS. EBS provides persistent block storage for EC2 instances and comes in different volume types tailored for various workloads. Here, I’ll share key insights about the different storage options, characteristics of EBS volumes, performance optimization tips, and how to work with snapshots.

Types of AWS Storage

AWS offers several storage types, each suited for different use cases:

  • Instance Store: This is ephemeral storage, meaning it is temporary and only available while the instance is running. Once the instance is stopped or terminated, the data is lost.

  • S3 (Simple Storage Service): AWS’s object storage service, with options like Standard and Reduced Redundancy Storage (RRS), which differ in their levels of durability and cost.

  • EBS (Elastic Block Store): The most common block storage option for EC2, offering various volume types including General Purpose SSD (GP-SSD), Provisioned IOPS SSD (PIOPS), and Magnetic.

  • EFS (Elastic File System): A managed network-attached storage option that supports Linux instances, allowing you to share files across multiple EC2 instances.

EBS Characteristics

EBS is flexible and resilient, designed for high availability and durability. Here are some key characteristics:

  • Billing: EBS is billed based on both storage capacity and I/O operations.
  • Detachable and Re-attachable: EBS volumes can be detached from one instance and reattached to another, allowing for flexibility in usage.
  • Availability: EBS volumes are tied to a specific Availability Zone but are replicated across multiple servers within that zone to reduce the risk of failure.
  • Reliability: EBS has an annual failure rate (AFR) of 0.1% to 0.2%, significantly lower than typical hard drives (5-10%).
  • SLA: EBS offers a 99.95% availability service level agreement (SLA).

EBS Volume Types

AWS offers several EBS volume types, each designed for specific workloads:

  1. General Purpose SSD (GP-SSD)
    • Use cases: Suitable for system boot volumes, virtual desktops, small to medium databases, and development/test environments.
    • Volume size: Ranges from 1GB to 16TB.
  2. Provisioned IOPS SSD (PIOPS)
    • Use cases: Best for I/O-intensive applications like relational databases and NoSQL databases.
    • Volume size: Ranges from 4GB to 16TB.
  3. Magnetic
    • Use cases: Ideal for infrequently accessed data or archiving, although SSD is becoming more affordable.
    • Volume size: Ranges from 1GB to 1TB.

Increasing IOPS Performance

For workloads that require higher IOPS performance, there are several optimization strategies:

  • RAID-0 Stripping: By combining multiple EBS volumes into a RAID-0 configuration, you can increase the total IOPS since the performance of each volume is aggregated. This can be a cheaper alternative to Provisioned IOPS but carries a higher risk—if one disk fails, all data could be lost. RAID-5 or RAID-6 could be more reliable but are still controlled by the guest OS.

  • EBS-Optimized Instances: These instances provide dedicated capacity for EBS I/O and can offer between 500 to 4000 Mbps in performance boosts. EBS-optimized instances are available for instance families like C, D, M, R, and G, although performance varies by type. AWS documentation provides more detailed specifications based on instance type.

Working with Snapshots

EBS snapshots are point-in-time backups of your volumes and are stored in S3. Snapshots provide a valuable tool for data recovery, backup, and migration across regions.

Snapshot Characteristics:

  • Incremental: Snapshots are incremental, meaning only the data that has changed since the last snapshot is stored, which saves space and reduces costs.
  • Dependent Snapshots: If you delete a snapshot, AWS automatically removes only the data not needed by any other snapshot, so there’s no risk of losing critical information.

Best Practices:

  • Power Down for Clean Snapshots: When taking a snapshot of a running instance, keep in mind that it may not capture an exact state if there’s ongoing activity. For a “clean cutover,” it’s recommended to power down the instance before taking a snapshot.

  • Pre-warming: Lazy loading from S3 can be slow, especially for large volumes. To improve performance, use tools like dd for Windows to read all blocks at once, effectively pre-warming the EBS volume for faster recall.

  • Sharing and Copying Snapshots: EBS snapshots can be shared between AWS accounts and copied across regions, providing flexibility for disaster recovery and backups.

  • Create AMIs from Snapshots: You can create Amazon Machine Images (AMI) from your snapshots, allowing you to launch new EC2 instances directly from a snapshot.

Final Thoughts

Amazon EBS provides flexible and reliable storage for a wide range of use cases. Whether you need high IOPS for a production database or low-cost magnetic storage for archiving, AWS has a volume type that fits the bill. Optimizing performance through RAID-0, leveraging EBS-optimized instances, and effectively managing snapshots can significantly enhance the efficiency of your AWS infrastructure.

For anyone preparing for the AWS SysOps Administrator certification exam, understanding the nuances of EBS storage types, performance optimization techniques, and snapshot management is essential. With the right knowledge, you’ll be able to design scalable, cost-effective storage solutions that meet your workload requirements.