Tag Archives: aws s3

AWS EC2, S3, RDS revision before the CSA exam

Leave a reply

Quick revision on topics AWS EC2, S3, RDS before appearing AWS Certified Solutions Architect – Associate exam.

EC2, S3, RDS revision!

This article notes down a few important points about AWS (Amazon Web Services) EC2, S3, and RDS. This can be helpful in last-minute revision before appearing for the AWS Certified Solutions Architect – Associate level certification exam.

This is first part of AWS CSA revision series. Rest of the series listed below :

In this article, we are checking out key points about EC2 (Elastic Compute Cloud), S3 (Simple Storage Service) and RDS (Relational Database Service).

Recommended read : AWS CSA exam preparation guide

Lets get started :

EC2 (Elastic Compute Cloud)

  • Its an AWS service that provides scalable virtual servers in cloud.
  • Pricing models are Reserved instances, On-demand instances, and spot instances.
  • Reserved are less costly since you reserve in advance by paying partial or full.
  • On-demand ones are costliest. But their launching depends on current available capacity in that zone
  • Spot instances are bidding unused instances in the Amazon marketplace (cheapest of all). They are allocated and withdrawn according to your bid price.
  • Max 20 running and 20 shut-down instances can exist per account.
  • AMI is Amazon Machine Image used to deploy/install the pre-configured OS on EC2 instances.
  • Instance store backed volumes are ephemeral storage and lost their data once the instance is off
  • EBS (Elastic Block Store) volumes hold data permanently regardless of instance state.
  • EBS volume size: Min 1 GiB, Max 16384 GiB (16 Tib)
  • EBS volume can be attached to 1 instance at a time. It cannot be attached to an instance in a different availability zone.
  • EBS : 3 IOPS per GiB with a minimum of 100 IOPS, burstable to 3000 IOPS
  • EBS Provisioned IOPS. 50:1 ratio to be maintained.
  • RAID 5 and RAID 6 are not recommended for EBS by AWS.
  • IOPS are measures in chucks of 256KB or smaller.
  • EC2-Classic is a deprecated service. Exist in accounts before 24 Dec 2013.
  • The default session timeout for ELB is 60 sec.
  • 5 Elastic IPs per region only.
  • Key pairs are used by EC2 and CloudFront only.
  • SAML URL https://signin.aws.amazon.com/saml
  • Maximum 2 key pairs can be kept per user.
  • Elastic Load Balancer ELB modes :
    • Idle connection timeout
    • Cross zone load balancing
    • Connection draining
    • Proxy protocol
    • Sticky session
    • Health checks
  • Auto Scaling plans :
    • Current instant levels
    • Manual scaling
    • Dynamic scaling
    • Scheduled scaling
  • ELB session timeout is 60 sec.
  • Timeout for connection draining in ELB is 1 sec to 3600 sec. The default is 300 sec.

S3 (Simple Storage Service)

  • objects (files) are stored in buckets. All root folders are buckets and must have a unique name across all AWS infra
  • Unlimited storage and high availability by default
  • 99.999999999% (Eleven 9’s) durability and 99.99% availability for data stored on S3
  • User can enable AES-256 encryption for data at rest
  • Versioning can be enabled but can not be disabled. It can only be suspended then.
  • Life cycle policies can be defined for deletion or archival.
  • The glacier is a low-cost storage option for archiving data. Data in and out of Glacier takes hours or days.
  • Glacier costs 1 cent / 1 GB for a year.
  • Object size : min 0 bytes, max 5 TB
  • Object more than 100MB must use the multipart upload function
  • All regions support read after write consistency for PUTS (new object) and eventual consistency for PUTS (overwrite) & DELETE.
  • The object always stays within the region and synced across all availability zones.
  • The S3 infrequent access (S3-IA) storage class has object durability of 99.999999999% and availability of 99.90%
  • Max object size in a single put is 5GB.

RDS (Relation Database Service)

  • Its fully managed database service in the cloud.
  • Supported databases: Oracle, MySQL, PostgreSQL, MS SQL, Aurora (Amazon homegrown SQL DB)
  • Scale underlying hardware automatically
  • Support read replicas of SQL based DB
  • Disk space : min 5GB, max 3TB
  • Default database port: 3306
  • RDS backup retention policy : 0 days min (no backup) to 35 days max.

DynamoDB

  • Dynamodb supports in-place atomic updates
  • Dynamodb defaults in the US west Oregon region.
  • Max 1MB of data can be retrieved in the single query operation.
  •