Durability and replication are vital aspects to consider when preparing for the AWS Certified Solutions Architect – Associate (SAA-C03) exam. Within AWS, you can find a vast selection of storage solutions, each with unique features and characteristics. Let’s take a closer look at some of these.

Table of Contents

Amazon Simple Storage Service (Amazon S3)

Amazon S3 is an object storage service known for its industry-leading scalability, data availability, security, and performance.

  • Durability: Amazon S3 boasts 99.999999999% durability. This means data loss is extremely unlikely.
  • Replication: S3’s Replication feature automatically duplicates your data to a destination bucket of your choice in any AWS region. This helps to distribute the workload and reduce latency.

Here is a basic example of how you can upload a file to S3 storage using AWS CLI:

aws s3 cp my-file.txt s3://my-bucket/

Amazon Elastic Block Store (Amazon EBS)

Amazon Elastic Block Store (EBS) provides raw block-level storage that can be attached to Amazon EC2 instances.

  • Durability: You can snapshot your EBS volumes for backup purposes. These snapshots can help with disaster recovery, migrating data across regions and accounts, improving backup compliance, or creating a new volume’s baseline.
  • Replication: EBS volumes are automatically replicated within its Availability Zone (AZ) to protect against component failure, thus offering high availability and durability.

Amazon Elastic File System (Amazon EFS)

Amazon Elastic File System (EFS) is a scalable, elastic, POSIX-compatible file system designed for the AWS Cloud.

  • Durability: Files stored on EFS are automatically and redundantly stored across multiple Availability Zones.
  • Replication: With EFS Replication, you can manage the replication of data at the file system level.

Amazon S3 vs EBS vs EFS – Key feature comparison

Feature Amazon S3 Amazon EBS Amazon EFS
Storage Type Object-based Block-level Shared files
Max Throughput Virtually unlimited 75000 IOPS 10+ GBPS
Max Capacity Unlimited 16 TB Unlimited
Replication Cross regions Across multiple Availability Zones in a region Across multiple Availability Zones
Durability 99.999999999% 99.999% 99.999999999%

In conclusion, a deeper understanding of these AWS storage options and their characteristics like durability and replication, is instrumental both for making informed decisions in architectural design and for passing the AWS Certified Solutions Architect – Associate (SAA-C03) exam. Note, the best storage solution is reliant on the specific needs of your application or organization.

Practice Test

Amazon S3 offers a replication feature that allows you to create a copy of your data to another region.

  • True
  • False

Answer: True

Explanation: Amazon S3’s Cross-Region Replication (CRR) enables automatic, asynchronous copying of objects across buckets in different AWS Regions.

The durability of Amazon S3 is 999999999%.

  • True
  • False

Answer: True

Explanation: Amazon S3 Standard, S3 Standard-IA, S3 One Zone-IA, and S3 Intelligent-Tiering are all designed to provide 999999999% durability of objects over a given year.

When using Amazon EBS, data is replicated across multiple Availability Zones to prevent the loss of data from the failure of any single component.

  • True
  • False

Answer: False

Explanation: EBS data is automatically replicated within its Availability Zone, not across multiple zones, to protect from component failure.

Which of the following AWS Storage services offers Read Replicas feature?

  • Amazon S3
  • Amazon EBS
  • Amazon RDS
  • Amazon Glacier

Answer: Amazon RDS

Explanation: Amazon Relational Database Service (RDS) supports Read Replicas, which allow you to create one or more read-only copies of your database.

Glacier storage class of Amazon S3 is designed for long term archiving and backup purposes.

  • True
  • False

Answer: True

Explanation: Amazon S3 Glacier and S3 Glacier Deep Archive are a secure, durable, and extremely low-cost Amazon S3 cloud storage classes for data archiving and long-term backup.

Amazon EFS is a fully managed file system service that can be accessed by multiple EC2 instances simultaneously.

  • True
  • False

Answer: True

Explanation: Amazon EFS provides a simple, scalable, fully managed elastic NFS file system for use with AWS Cloud services and on-premises resources. It is built to serve thousands of concurrent connections and multiple EC2 instances can read and write to an EFS file system concurrently.

Is it possible to do cross region replication of EBS snapshots?

  • True
  • False

Answer: True

Explanation: You can copy a snapshot of an Amazon EBS volume to the same region or another region.

Which AWS service uses SSD storage for high frequency read and write access?

  • Amazon EFS
  • Amazon EBS
  • Amazon Glacier
  • Amazon RDS

Answer: Amazon EBS

Explanation: Amazon EBS provides both SSD-backed storage for high frequency read and write access.

Do Amazon RDS Read Replicas provide failover support for DB instances?

  • True
  • False

Answer: False

Explanation: Amazon RDS Read Replicas provide additional read and write scalability, not failover support.

You can restore files deleted from Amazon Glacier immediately.

  • True
  • False

Answer: False

Explanation: Glacier has a retrieval delay, typically 3-5 hours, and is not suitable for immediate retrievals.

Amazon S3 data is automatically encrypted at rest.

  • True
  • False

Answer: False

Explanation: Encryption is available and strongly recommended, but it’s not automatic – you need to enable it.

Interview Questions

What does durability refer to in terms of storage on AWS?

Durability refers to the measure of the ability to prevent data loss. In AWS, durability is usually expressed as a percentage with Amazon S3 Standard, for instance, offering 99.999999999% durability.

What does replication mean in AWS storage?

Replication in AWS storage refers to the automatic copying of data across different regions or buckets. This ensures data redundancy and availability, which can protect against data loss due to unplanned events.

Can you explain AWS S3’s cross-region replication (CRR)?

AWS S3’s cross-region replication (CRR) is an automatic, asynchronous process which replicates every object (including all subsequent updates) uploaded to S3 buckets to a destination bucket located in a different AWS region.

What is the durability of objects stored in Glacier Vault Lock?

Glacier Vault Lock provides the same 99.999999999% durability that Amazon S3 provides.

What is horizontal scaling in terms of Amazon DynamoDB?

Horizontal scaling in Amazon DynamoDB refers to the process of adding more partitions to a table to get higher throughput levels. It is also known as data partitioning.

What roles do AWS S3 and Glacier play in data lifecycle management?

AWS S3 and Glacier can automatically transition objects between different storage classes depending on their lifecycle policy. This allows for cost-effective management of objects throughout their lifecycle, transitioning them to a different storage tier (Glacier for instance) when it’s more cost-effective but still needed.

In terms of data storage, what is the meaning of eventual consistency in AWS?

Eventual consistency in AWS means that all changes to a piece of data will propagate through the system eventually, reaching a state in which all copies of the data are the same. This condition is typically achieved in less than a second.

How does versioning protect data in Amazon S3?

Versioning in Amazon S3 is a means of keeping multiple variants of an object in the same bucket. With versioning, you can preserve, retrieve, and restore every version of every object in your bucket. This means you can recover from both unintended user actions and application failures.

What is the EBS Snapshot in AWS?

An EBS Snapshot is a point-in-time copy of your data. It is a block-level, incremental backup that only captures the changed parts of your Amazon EBS volume after your last snapshot.

What does IOPS mean in relation to Amazon EBS volumes?

IOPS stands for Input/Output Operations Per Second, a common performance measurement used to benchmark computer storage devices like hard disk drives (HDD), solid state drives (SSD), and storage area networks (SAN). In Amazon EBS, it’s a unit that measures the number of read and write operations to an EBS volume.

Which service would you use for a hot storage tier on AWS?

For a hot storage tier, where frequently accessed data needs to be available immediately, options could include Amazon S3 Standard or Amazon EBS Provisioned IOPS.

What is Amazon S3 One-Zone Infrequent Access storage class?

Amazon S3 One-Zone Infrequent Access, or S3 One Zone-IA, is a storage class designed for long-lived, but less frequently accessed data. Unlike other S3 Storage Classes which store data in a minimum of three Availability Zones (AZs), S3 One Zone-IA stores data in a single AZ, providing cost savings.

How does Amazon S3 ensure data integrity?

Amazon S3 auto-checks all data uploaded and downloaded from the service using checksums, ensuring data integrity.

How is data encrypted in AWS S3?

AWS S3 provides encryption features for data at rest and during transit. The two main forms of encryption it supports are client-side encryption (where data is encrypted before it is sent to S3) and server-side encryption (where data is encrypted in-storage).

What are the main characteristics of EFS (Elastic File System) on AWS?

EFS is a file storage service for Amazon EC2 instances. It is highly durable and can grow and shrink as needed (elastic). It enables data to be accessed by multiple EC2 instances at a time and provides consistent low latencies. It also supports file system semantics and directory hierarchies.

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