volume basics
We need EBS (Elastic Block Store) volumes in AWS because they provide durable, persistent, block-level storage that can be attached to EC2 instances, functioning like a hard drive for storing data that requires frequent updates or continuous access. EBS volumes are essential for operating systems, databases, application code, logs, and throughput-intensive or I/O-sensitive workloads. They persist independently from the life of the instance, so data remains intact even if the instance stops or terminates.
Volumes in AWS, specifically Amazon EBS (Elastic Block Store) volumes, are durable, block-level storage devices that you attach to Amazon EC2 instances to provide persistent storage, similar to a physical hard drive attached to a computer.
Key aspects of AWS EBS volumes
Block-level storage: These volumes appear to the EC2 instance like a hard drive, allowing you to store files, install applications, or host databases.
Persistence: Data on an EBS volume persists independently of the EC2 instance’s lifecycle. This means your data remains intact even if the instance is stopped or terminated.
Flexibility and scalability: You can dynamically modify size, performance (IOPS), and volume type on live volumes without downtime, making them adaptable to changing workload requirements.
Multiple volume types: AWS offers a variety of EBS volume types optimized for different use cases:
SSD-backed volumes (General Purpose SSD gp2/gp3, Provisioned IOPS SSD io1/io2) for transactional workloads requiring low latency and high IOPS.
HDD-backed volumes (Throughput Optimized HDD st1, Cold HDD sc1) for throughput-intensive or infrequently accessed workloads.
High availability and durability: Data on EBS volumes is automatically replicated within the same Availability Zone to protect against hardware failures and ensure durability, with some volume types providing up to 99.999% durability.
Backup and recovery: You can create snapshots of EBS volumes, which are incremental backups stored in Amazon S3, enabling easy restoration or migration of data.
Security: EBS volumes support encryption using AWS Key Management Service (KMS), protecting data at rest and in transit between instances and volumes.
Key reasons why EBS volumes are needed in AWS
Persistent storage: Unlike instance store volumes that are ephemeral and lost when an instance stops or terminates, EBS volumes retain data independently, enabling reliable long-term storage for EC2 instances.
Flexibility and scalability: You can dynamically resize volumes, adjust performance (such as IOPS), and change volume types on live production workloads. This scalability supports various application needs, from boot volumes to large databases.
Performance tailoring: Multiple volume types (General Purpose SSD, Provisioned IOPS SSD, Throughput Optimized HDD, Cold HDD) let you select storage optimized for cost, throughput, or IOPS depending on your workload.
Data availability and durability: EBS volumes replicate data within an Availability Zone to prevent hardware failure data loss, ensuring high availability and durability.
Multiple attachments and shared storage: Some volume types support Multi‑Attach, allowing a single volume to be attached to multiple Nitro‑based instances, facilitating shared data access.
Use cases: EBS volumes are suitable for storing operating system files, application code, databases, logs, temporary files, and throughput‑intensive workloads which need persistent, high‑performance storage on AWS.
Contrast with other AWS storage services
While other AWS storage services like S3 provide object storage, and RDS offers managed databases, EBS volumes uniquely provide block-level, persistent storage that behaves like a traditional disk attached to an EC2 instance, suitable for OS boot drives and workloads requiring frequent random I/O.
In summary: EBS volumes provide EC2 instances with reliable, scalable, and performant disk storage that persists independently from the instance lifecycle—making them critical for most production applications on AWS.