Lesson 7: EC2 instance stores

Question 1

EBS Overview

Answer 1

EBS Volumes are network-attached storage devices that persist data beyond instance termination.
Each EBS Volume is bound to a specific availability zone and can only be attached to one EC2 instance at a time.
EBS Volumes require provisioning of capacity and IOPS in advance, with billing based on provisioned resources.
The “Delete on Termination” attribute controls whether EBS Volumes are deleted when the associated EC2 instance is terminated.

Question 2

EBS Snapshots

Answer 2

EBS Snapshots serve as backups of EBS volumes at any point in time without necessarily detaching the volume from the EC2 instance.
Snapshots can be copied across different Availability Zones and Regions, facilitating volume transfer.
The EBS Snapshot Archive tier offers up to 75% cost savings but requires 24 to 72 hours for restoration.
The Recycle Bin feature allows recovery of accidentally deleted snapshots with retention periods from one day to one year.
Fast Snapshot Restore enables immediate volume initialization with zero latency on first use but incurs higher costs.

Question 3

AMI Overview

Answer 3

An AMI (Amazon Machine Image) customizes EC2 instances with preconfigured software and operating systems.
Creating your own AMI results in faster boot and configuration times for EC2 instances.
AMIs can be region-specific but can be copied across AWS regions to leverage global infrastructure.
AWS Marketplace offers AMIs created and sold by third parties, enabling users to save time or even sell their own AMIs.

Amazon Machine Image (AMI) is specific to the region it was created in. This means that if you create an AMI in the N. Virginia region, you can’t use it directly to launch an EC2 instance in a different region.

Question 4

EC2 Instance Store

Answer 4

EC2 Instance Store provides hardware-attached disk storage for EC2 instances, offering extremely high I/O performance.
Instance Store storage is ephemeral and data is lost if the instance is stopped or terminated.
Ideal use cases for Instance Store include buffers, caches, and temporary data, but not long-term storage.
Users are responsible for backing up and replicating data stored on Instance Store to prevent data loss.

Question 5

EBS Volume Types

Answer 5

EBS volumes come in six types: gp2, gp3, io1, io2 Block Express, st1, and sc1.
gp2 and gp3 are general purpose SSDs balancing price and performance; gp3 allows independent scaling of IOPS and throughput.
io1 and io2 are high-performance provisioned IOPS SSDs for mission-critical workloads, with io2 Block Express offering up to 256,000 IOPS.
st1 and sc1 are HDD volumes optimized for throughput and cost, respectively, and cannot be used as boot volumes.

By default, the Root EBS volume of an EC2 instance is set to be deleted upon termination, while any additional EBS volumes remain undeleted, allowing you to retain data even after the instance is terminated.

Question 6

EBS Multi-Attach

Answer 6

The Multi-Attach feature allows the same EBS volume to be attached to multiple EC2 instances within the same availability zone.
This feature is available only for the io1 and io2 families of EBS volumes.
Up to 16 EC2 instances can simultaneously attach to the same volume.
A cluster-aware file system is required to use Multi-Attach effectively.

Question 7

EBS Encryption

Answer 7

Encrypting an EBS volume secures data at rest, in transit, snapshots, and derived volumes transparently.
Encryption uses AES-256 and integrates with AWS KMS keys with minimal latency impact.
To encrypt an unencrypted EBS volume, create a snapshot, copy it with encryption enabled, then create a new encrypted volume from that snapshot.
The AWS console allows enabling encryption on the fly when creating volumes from snapshots, simplifying the process.

Question 8

Amazon Elastic File System (EFS) Overview

Answer 8

Amazon EFS is a managed NFS network file system that can be mounted on multiple EC2 instances across different availability zones.
EFS offers high availability, scalability, and pay-per-use pricing without the need to provision capacity in advance.
It supports Linux-based AMIs only, provides encryption at rest via KMS, and uses POSIX standard file APIs.
Various performance modes, throughput modes, and storage classes allow customization for different workloads and cost optimization.

Question 9

EFS vs EBS

Answer 9

EBS volumes are attached to a single EC2 instance at a time and are locked to a specific Availability Zone (AZ).
EBS IO performance varies by volume type, with gp3 and io1 allowing independent IO scaling.
Migrating EBS volumes across AZs requires creating and restoring snapshots.
EFS is a network file system designed to be shared across multiple instances and AZs, supporting POSIX and suitable for Linux workloads.
EFS generally has a higher cost but offers storage tiers for cost optimization.
Instance store volumes are physically attached to EC2 instances and data is lost if the instance is terminated.