[Tips] AWS Solution Architect – Associate

  • Amazon S3 buckets in all Regions provide read-after-write consistency for PUTS of new objects and eventual consistency for overwrite PUTS and DELETES.
  • High IO needs -> RAID 10 : Striped and Mirrored, Good Redundancy, Good Performance
  • S3
    • Standard : 99.999999999% durability, 99.99% availability
    • S3-IA (Infrequent Access) : 99.999999999% durability, 99.9% availability (You should expect the same latency and throughput performance as Amazon S3 Standard when using Standard – IA.)
    • S3-RRS (Reduced Redundancy Storage) : 99.99% durability, 99.99% availability
    • Glacier : 99.999999999% durability, 3-5 hours via the Amazon S3 APIs or Management Console

  • Amazon Redshift uses a block size of 1 MB, which is more efficient and further reduces the number of I/O requests needed to perform any database loading or other operations that are part of query execution.
  • ECS doesn’t work without the ECS agent
  • 1 subnet = 1 availability zone; multiple A-Z -> multiple subnets
  • It is possible to transfer a reserved instance from one Availability Zone to another.
  • A placement group is a logical grouping of instances within a single Availability Zone. Placement groups are recommended for applications that benefit from low network latency, high network throughput, or both.
    • A placement group can’t span multiple Availability Zones.
    • The name you specify for a placement group must be unique within your AWS account.
    • Only certain types of instances can be launched in a placement group.
    • AWS recommend homogeneous instances within placement groups.
    • You can’t merge placement groups
    • You can’t move an existing instance into a placement group
  • By default, new subnets in a custom VPC can communicate with each other across Availability Zones.
  • For all new AWS accounts, there is a soft limit of 20 EC2 instances per region. You should submit the limit increase form and retry the template after your limit has been increased.
  • The names of the AZs are randomly applied, so “eu-west-1b” is not necessarily the same physical location for all three accounts.
  • Encryption :
    • server-side
      • SSE-S3 : Each object is encrypted with a unique key employing strong multi-factor encryption.
      • SSE-KMS : Similar to SSE-S3, but with some additional benefits along with some additional charges for using this service.
      • SSE-C : You manage the encryption keys and Amazon S3 manages the encryption, as it writes to disks, and decryption, when you access your objects.
    • client-side
      • AWS KMS-CMK : only encrypted objects are transmitted over the Internet to Amazon S3.
      • client-side master key
  • Instance types : T/M C X/R P/G/F I/D
  • Amazon’s SLA guarantees a Monthly Uptime Percentage of at least 99.95% for Amazon EC2 and Amazon EBS within a Region.
  • S3 Minimum
    • Standard – IA is designed for larger objects and has a minimum object size of 128KB. Objects smaller than 128KB in size will incur storage charges as if the object were 128KB.
    • S3 – The mininum object size is 0 Bytes. Most often, this will be a “touched” file.
  • Multipart Upload is recommended for files greater than 100 Mb, and is required for files 5 GB or larger.
  • S3 Transfer Accelearation is especially useful in cases where your bucket resides in a Region other than the one in which the file transfer was originated.
  • Only the owner of an Amazon S3 bucket can permanently delete a version.
  • A Dedicated Host is required if you’d like to use your existing Windows Server licenses.
  • Limits
    • By default, all accounts are limited to 5 Elastic IP addresses per region.
    • By default, customers can provision up to 100 buckets per AWS account. However, you can increase your Amazon S3 bucket limit by visiting AWS Service Limits.
    • With Route 53, there is a default limit of 50 domain names. However, this limit can be increased by contacting AWS support.
  • EBS Snapshots are versioned and you can read an older snapshot to do a point-in-time recovery
  • Amazon CloudWatch stores metrics for terminated Amazon EC2 instances or deleted Elastic Load Balancers for 2 weeks.
  • The two different types of virtualzation available are Hardware Virtual Machine (HVM) & Paravirtual Machine (PVM)
  • Amazon’s ELB supports the following protocols – “HTTP, HTTPS, TCP, SSL”
  • Storage Gateway
    • Stored
    • Cached : Storage Gateway with Gateway-Cached Volumes would store your most frequently-accessed data on-premise, and would write your other data to S3.
  • RDS : 6TB
  • SQL Server : There are two different limits – that of the DB (10GB), and that of the DB instance server storage (300GB). A DB server instance could quite easily host several DBs, or a DB and support files such as logs, dumps, and flat file backups.
  • RDS retention : max 35 days
  • With Multi-AZ RDS instances and automated backups, I/O activity is no longer suspended on your primary during your preferred backup window, since backups are taken from the standby.
  • Access keys should never be stored on an AMI
  • You can use SSH to access the underlying operating systems of EMR and EC2.
  • Your bucket name always comes first, “s3-website” followed by the Region always comes next.
  • You can use AWS Config to continuously record configurations changes to Amazon RDS DB Instances, DB Subnet Groups, DB Snapshots, DB Security Groups, and Event Subscriptions and receive notification of changes through Amazon Simple Notification Service (SNS).
  • Read Replicate – asynchronous; Multi-AZ – synchronous
  • Read Replicas are supported by Amazon RDS for MySQL and PostgreSQL
  • The AMIs will need to be copied to the new Region prior to deployment.
  • 50 VMs can be migrated concurrently.
  • SWF task and workflow execution can last up to one year, and can include (and depend on) tasks to be performed by on-premises servers and humans.
  • The data from an EBS volume snapshot is durable because EBS snapshots are stored on the Amazon S3-Standard. Data stored on EBS volumes is automatically and redundantly stored in multiple physical volumes in the same availability zone as part of the normal operations of the EBS service at no additional charge.
  • With proper scripting and scaling policies, the On-demand instances behind the Spot instances will deliver the most cost-effective solution because the on-demand will only spin up if the spot instances are not available.
  • DynamoDB is a regional service, there is no need to explicitly create a multi-AZ deployment. RDS could be used, but DynamoDB lends itself better to supporting stateless web/app installations.
  • The Public IP address is not managed on the instance: It is, instead, an alias applied as a network address translation of the Private IP address.

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