EC2 Storage: EBS, Instance Store, and Volume Types - Vocabulary Flashcards

Vocabulary flashcards covering EBS concepts, encryption with KMS, snapshots, volume types (gp2, gp3, io1/io2), Multi-Attach, HDD-based volumes, and Instance Store from the lecture notes.

Elastic Block Store (EBS)

Block-level storage volumes for EC2 that are persistent, AZ-scoped, support snapshots, and can be encrypted with KMS.

Block storage

Storage organized in fixed-size blocks; used by operating systems for boot drives and file systems, enabling direct block access.

AZ-scoped

An EBS volume is tied to a specific Availability Zone and cannot be attached to an instance in a different AZ.

Snapshots

Point-in-time backups of EBS volumes stored in S3; first snapshot copies the entire volume, later snapshots are incremental and regional.

Incremental snapshots

Subsequent snapshots that only store blocks changed since the last snapshot, after the initial full snapshot.

Encryption (EBS)

Data at rest and in transit encrypted via AWS KMS; encryption state is per-volume; encrypted snapshots/volumes require appropriate KMS handling.

CMK (Customer Master Key)

The KMS key you control (customer-managed or AWS-managed) used to encrypt the DEK; access controlled by IAM.

Data Encryption Key (DEK)

The actual key that encrypts data on the EBS volume; unique per volume, encrypted by the CMK, and shared across snapshots and derived volumes.

DEK inheritance

The same DEK is used for the parent volume, all its snapshots, and volumes created from those snapshots; all tied to the same KMS key.

DeleteOnTermination

Flag on the root volume that determines whether the root EBS volume is deleted when the instance is terminated.

GP2 (General Purpose SSD)

Legacy general-purpose SSD; baseline 3 IOPS per GiB; can burst up to 3,000 IOPS using credits; balance of price and performance.

GP3 (General Purpose SSD)

Current generation general-purpose SSD; baseline 3,000 IOPS and 125 MiB/s; IOPS/throughput can be provisioned independently of storage size; often cheaper per GiB.

Provisioned IOPS (io1, io2, io2 Block Express)

IOPS you explicitly provision for high-performance workloads; you pay for provisioned capacity whether used or not.

IOPS

Input/Output Operations Per Second; a key performance metric for EBS volumes.

IO2 durability

io2 offers 99.999% durability, higher than io1 and other EBS types, suited for very critical workloads.

IO2 Block Express

Next-generation architecture delivering the highest performance with sub-millisecond latency; ideal for the largest, most I/O-intensive deployments.

Multi-Attach

Feature allowing a single io1/io2 volume to attach to multiple EC2 instances in the same AZ; requires cluster-aware applications.

When to use Provisioned IOPS

Use for mission-critical, I/O-intensive workloads or when IOPS requirements exceed gp3 limits (>16,000 IOPS).

HDD-backed volumes (st1, sc1)

Magnetic volumes focused on throughput (MiB/s) rather than IOPS; st1 is throughput-optimized, sc1 is cold HDD; cannot be boot volumes.

Boot volume restriction

Boot volumes must be SSD-based (gp2/gp3/io1/io2); HDD-based volumes cannot be used as boot volumes.

Instance Store

Temporary, high-performance storage physically attached to the host; data persists only for the life of the instance; no snapshots or resizing; attached at launch; cost included in the instance price.

Instance Store data persistence rules

Data is lost if the instance stops, terminates, hibernates, or the host fails; reboot preserves data; stop/start may lose data.

Snapshot vs Volume billing

Volumes are billed by allocated size; snapshots are billed by actual data stored in S3 (pay-for-use, with 11 nines durability in S3, and incremental storage).