AWS S3 Storage Classes – Certification

AWS S3 Storage Classes Overview

  • Amazon S3 storage classes are designed to sustain the concurrent loss of data in one or two facilities
  • S3 storage classes allows lifecycle management for automatic migration of objects for cost savings
  • S3 storage classes support SSL encryption of data in transit and data encryption at rest
  • S3 also regularly verifies the integrity of your data using checksums and provides auto healing capability

AWS S3 Storage Classes Comparision

Standard

  • Storage class is ideal for performance-sensitive use cases and frequently accessed data and is designed to sustain the loss of data in a two facilities
  • STANDARD is the default storage class, if none specified during upload
  • Low latency and high throughput performance
  • Designed for durability of 99.999999999% of objects
  • Designed for 99.99% availability over a given year
  • Backed with the Amazon S3 Service Level Agreement for availability.

Standard IA

  • S3 STANDARD_IA (Infrequent Access) storage class is optimized for long-lived and less frequently accessed data for e.g. backups and older data where access is limited, but the use case still demands high performance
  • STANDARD_IA is designed to sustain the loss of data in a two facilities
  • STANDARD_IA objects are available for real-time access.
  • STANDARD_IA storage class is suitable for larger objects greater than 128 KB (smaller objects are charged for 128KB only) kept for at least 30 days.
  • Same low latency and high throughput performance of Standard
  • Designed for durability of 99.999999999% of objects
  • Designed for 99.9% availability over a given year
  • Backed with the Amazon S3 Service Level Agreement for availability

Reduced Redundancy Storage – RRS

  • Reduced Redundancy Storage (RRS) storage class is designed for noncritical, reproducible data stored at lower levels of redundancy than the STANDARD storage class, which reduces storage costs
  • Designed for durability of 99.99% of objects
  • Designed for 99.99% availability over a given year
  • Lower level of redundancy results in less durability and availability
  • RRS stores objects on multiple devices across multiple facilities, providing 400 times the durability of a typical disk drive,
  • RRS does not replicate objects as many times as S3 standard storage and is designed to sustain the loss of data in a single facility.
  • If an RRS object is lost, S3 returns a 405 error on requests made to that object
  • S3 can send an event notification, configured on the bucket, to alert a user or start a workflow when it detects that an RRS object is lost which can be used to replace the lost object

Glacier

  • GLACIER storage class is suitable for archiving data where data access is infrequent and retrieval time of several (3-5) hours  is acceptable.
  • GLACIER storage class uses the very low-cost Amazon Glacier storage service, but the objects in this storage class are still managed through S3
  • Designed for durability of 99.999999999% of objects
  • GLACIER cannot be specified as the storage class at the object creation time but has to be transitioned fromSTANDARD, RRS, or STANDARD_IA to GLACIER storage class using lifecycle management.
  • For accessing GLACIER objects,
    • object must be restored which can taken anywhere between 3-5 hours
    • objects are only available for the time period (number of days) specified during the restoration request
    • object’s storage class remains GLACIER
    • charges are levied for both the archive (GLACIER rate) and the copy restored temporarily (RRS rate)
  • Vault Lock feature enforces compliance via a lockable policy

AWS Certification Exam Practice Questions

  • Questions are collected from Internet and the answers are marked as per my knowledge and understanding (which might differ with yours).
  • AWS services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
  • AWS exam questions are not updated to keep up the pace with AWS updates, so even if the underlying feature has changed the question might not be updated
  • Open to further feedback, discussion and correction.
  1. What does RRS stand for when talking about S3?
    1. Redundancy Removal System
    2. Relational Rights Storage
    3. Regional Rights Standard
    4. Reduced Redundancy Storage
  2. What is the durability of S3 RRS?
    1. 99.99%
    2. 99.95%
    3. 99.995%
    4. 99.999999999%
  3. What is the Reduced Redundancy option in Amazon S3?
    1. Less redundancy for a lower cost
    2. It doesn’t exist in Amazon S3, but in Amazon EBS.
    3. It allows you to destroy any copy of your files outside a specific jurisdiction.
    4. It doesn’t exist at all
  4. An application is generating a log file every 5 minutes. The log file is not critical but may be required only for verification in case of some major issue. The file should be accessible over the internet whenever required. Which of the below mentioned options is a best possible storage solution for it?
    1. AWS S3
    2. AWS Glacier
    3. AWS RDS
    4. AWS S3 RRS
  5. A user has moved an object to Glacier using the life cycle rules. The user requests to restore the archive after 6 months. When the restore request is completed the user accesses that archive. Which of the below mentioned statements is not true in this condition?
    1. The archive will be available as an object for the duration specified by the user during the restoration request
    2. The restored object’s storage class will be RRS (After the object is restored the storage class still remains GLACIER. Read more)
    3. The user can modify the restoration period only by issuing a new restore request with the updated period
    4. The user needs to pay storage for both RRS (restored) and Glacier (Archive) Rates
  6. Your department creates regular analytics reports from your company’s log files. All log data is collected in Amazon S3 and processed by daily Amazon Elastic Map Reduce (EMR) jobs that generate daily PDF reports and aggregated tables in CSV format for an Amazon Redshift data warehouse. Your CFO requests that you optimize the cost structure for this system. Which of the following alternatives will lower costs without compromising average performance of the system or data integrity for the raw data?
    1. Use reduced redundancy storage (RRS) for PDF and CSV data in Amazon S3. Add Spot instances to Amazon EMR jobs. Use Reserved Instances for Amazon Redshift. (Spot instances impacts performance)
    2. Use reduced redundancy storage (RRS) for all data in S3. Use a combination of Spot instances and Reserved Instances for Amazon EMR jobs. Use Reserved instances for Amazon Redshift (Combination of the Spot and reserved with guarantee performance and help reduce cost. Also, RRS would reduce cost and guarantee data integrity, which is different from data durability )
    3. Use reduced redundancy storage (RRS) for all data in Amazon S3. Add Spot Instances to Amazon EMR jobs. Use Reserved Instances for Amazon Redshift (Spot instances impacts performance)
    4. Use reduced redundancy storage (RRS) for PDF and CSV data in S3. Add Spot Instances to EMR jobs. Use Spot Instances for Amazon Redshift. (Spot instances impacts performance)
  7. Which of the below mentioned options can be a good use case for storing content in AWS RRS?
    1. Storing mission critical data Files
    2. Storing infrequently used log files
    3. Storing a video file which is not reproducible
    4. Storing image thumbnails

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