Udemy AWS SAA - EBS, AMI, EFS

EBS (Elastic Block Store) Volume

• it is a network drive you can attach to you instances while they run
• it allows you instances to persist data, even after their termination. Just like a "network USB stick" (not physical)
• they can only be mounted to one instance at a time. And it is bound to a specific availability zone

EBS - Delete on Termination Attribute

• can control preserve root volume when instance is terminated

EBS Snapshots

• Make a backup (snapshot) of your EBS volume at a point in time
• You can copy snapshot from AZ to AZ
• You can archive it so cheaper, it take 24-72 hrs for restoring the archive
• You can recover deleted snapshots from recycle bin
• FSR (Fast Snapshot Restore): force full initialization of snapshot to have no latency on the first use, but very expensive

AMI

• Amazon Machine Image, a customization of an EC2 instance, you can add your own software, configuration, OS, monitoring, so that faster boot / config time bc all your software is pre-packaged
  • Public AMI: AWS provided;
  • Your own AMI: make and maintain them yourself;
  • An AWS marketplace AMI: AMI made by someone else

AMI Process

EC instance store

• EBS volumes are good but (it's network drive) limited performance
• So we need a high-performance in I/O hardware disk, use EC2 instance store. But it lose storage if they are stopped, so ephemeral, only good for buffer / cache / scratch data / temporary content
• risk of data loss if hardware fails, so need to backup and replicate

EBS Volume Types

• gp2/gp3 (SSD): General purpose SSD volume that balances price and performance fora wide variety of workloads

• iol /io2 (SSD): Highest-performance SSD volume for mission-critical low-latency or high-throughput workloads

• stl (HDD): Low cost HDD volume designed for frequently accessed, throughput-intensive workloads

• scl (HDD): Lowest cost HDD volume designed for less frequently accessed workloads

• only gp2 / gp3 and io1 / io2 can be used as boot volumes

EBS Volume Use Case

• GP: gp3 can increase IOPS and throughput independently, but gp2's volume size and IOPS are linked
• Provisioned IOPS SSD: great for database workload (sensitive to storage performance and consistency)
• HHD: hard disk drives, cannot be a boot volume

Multi-attach feature of EBS, only available to io1/io2

• It allows us attach same EBS volume to multiple EC2 instances in the same AZ
• it's up to 16 EC2 instances at a time
  can achieve higher application availability in clustered linux app

EBS Encryption

• When you create an encrypted EBS volume, you get the following:
  • Data at rest is encrypted inside the volume
  • All the data in fight moving between the instance and the volume is encrypted
  • All snapshots are encrypted
  • All volumes created from the snapshot
• Encryption and decryption are handled transparently (you have nothing todo)
• Encryption has a minimal impact on latency
• EBS Encryption leverages keys from KMS (AES-256)

Amazon EFS- Elastic File System

• Managed NFS (network file system) that can be mounted on many EC2 EFS works with EC2 instances in multi-AZ
• Highly available, scalable, expensive (3x gp2), pay per use
• Use cases: content management, web serving, data sharing, Wordpress
• Uses NFSv4.l protocol
• Uses security group to control access to EFS
• Compatible with Linux based AMl (not Windows)
• Encryption at rest using KMS
• POSlX file system (~Linux) that has a standard file API
• File system scales automatically, pay-per-use, no capacity planning

EFS- Performance Classes

• EFS Scale
  • 1000s of concurrent NFS clients, 10 GB+ /s throughput
  • Grow to Petabyte-scale network file system, automatically
• Performance mode (set at EFS creation time)
  • General purpose (default): latency-sensitive use cases (web server, CMS, etc...)Max 1/O- higher latency, throughput, highly parallel (big data, media processing)
• Throughput mode
  • Bursting(lTB= 50MiB/s + burst ofup to 100MiB/s)
  • Provisioned: set your throughput regardless of storage size, ex: l GiB/s for l TB storage

EFS- Storage Classes

• Storage Tiers (lifecycle management feature -move file after N days)

  • Standard: for frequently accessed files
  • Infrequent Access (EFS-A): cost to retrieve fles,lower price to store. Enable EFS-lA with a Life cycle Policy

• Availability and durability

  • Standard: Multi-AZ, great for prod
  • One Zone: One AZ, great for dev, backup enabled by default, compatible with lA (EFS One Zone-lA)

• Mounting 100s of instances across AZ

• EFS share website files (WordPress)

• Only for Linux Instances (POSlx)

• EFS has a higher price point than EBS

• Can leverage EFS-IA for cost savings

EBS vs EFS
EBS

• EBS volumes..
  • can be attached to only one instance at a time
  • are locked at the Availability Zone (AZ) level
  • gp2: 1O increases if the disk size increases
  • iol: can increase lO independently
• To migrate an EBS volume across AZ
  • Take a snapshot
  • Restore the snapshot to another AZ
  • EBS backups use lO and you shouldn't run them while your application is handling a lot of traffic
• Root EBS Volumes of instances get terminatedby default if the EC2 instance gets terminated.(you can disable that)

EFS

• Mounting 100s of instances across AZ
• EFS share website files (WordPress)
• Only for Linux Instances (POSlx)
• EFS has a higher price point than EBS
• Can leverage EFS-A for cost savings

Remember: EFS vs EBS vs Instance Store