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EBS (Elastic Block Store)


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Amazon EBS provides persistent block storage volumes for use with EC2 instances.

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Key Concepts​

  • EBS volumes are network-attached storage that persist independently from the life of an EC2 instance
  • A volume can only be attached to one EC2 instance at a time (except for multi-attach io1/io2 volumes)
  • Volumes and instances must be in the same Availability Zone
  • Volumes can be detached and reattached to other instances in the same AZ
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Volume Types​

SSD-backed​

  • gp3 (General Purpose SSD): baseline of 3,000 IOPS and 125 MB/s; performance can be scaled independently; recommended for most workloads
  • gp2 (General Purpose SSD): baseline of 3 IOPS per GB, burstable up to 3,000 IOPS; older generation
  • io2 Block Express: up to 256,000 IOPS and 4,000 MB/s; designed for the most demanding I/O-intensive workloads
  • io1 (Provisioned IOPS SSD): up to 64,000 IOPS; for workloads requiring sustained IOPS performance

HDD-backed​

  • st1 (Throughput Optimized HDD): designed for frequently accessed, throughput-intensive workloads (e.g. big data, log processing)
  • sc1 (Cold HDD): lowest cost; designed for less frequently accessed workloads
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Snapshots​

  • Point-in-time backups of EBS volumes stored in S3
  • Snapshots are incremental (only the blocks that have changed since the last snapshot are saved)
  • Can be used to create new volumes in any AZ within the same region
  • Snapshots can be copied across regions
  • Can be shared with other AWS accounts or made public
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Encryption​

  • Uses AWS KMS keys for encryption
  • Encrypts data at rest, data in transit between the volume and the instance, all snapshots, and all volumes created from encrypted snapshots
  • Encryption is handled transparently with minimal impact on latency
  • Unencrypted volumes cannot be encrypted directly; create an encrypted snapshot and restore from it
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Multi-Attach​

  • Available for io1 and io2 volumes only
  • Allows a single volume to be attached to up to 16 EC2 instances simultaneously in the same AZ
  • Each instance has full read and write permissions to the volume
  • Requires a cluster-aware file system to manage concurrent access
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