AWS Database Flashcards

1
Q

What is the use case for Database on EC2?

A

Full control over instance and database

Preferred DB not available under RDS

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2
Q

What is the use case for Amazon RDS?

A

Need traditional relational database for OLTP
Your data is well-formed and structured
Existing applications requiring RDBMS

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3
Q

What is the use case for Amazon DynamoDB?

A
Name/value pair data
Unpredictable data structure
In-memory performance with persistence
High I/O needs
Require dynamic scaling
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4
Q

What is the use case for Amazon RedShift?

A

Data warehouse for large volumes of aggregated data

Primarily OLAP workloads

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5
Q

What is the use case for Amazon Neptune?

A

Relationships between objects are of high value

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6
Q

What is the use case for Amazon ElastiCache?

A

Fast temporary storage for small amounts of data

Highly volatile data (non-persistent)

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7
Q

What is the use case for Amazon S3?

A

Binary large objects (BLOBs)

Static websites

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8
Q

What is Amazon Relational Database Service (RDS)?

A

Amazon Relational Database Service (Amazon RDS) is a managed service that makes it easy to set up, operate, and scale a relational database in the cloud.

RDS is an Online Transaction Processing (OLTP) type of database.

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9
Q

What are Relational and Non-relational Databases known as?

A

Relational databases are known as Structured Query Language (SQL) databases.

Non-relational databases are known as NoSQL databases.

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10
Q

What are the benefits of Amazon RDS?

A

SQL type of database.
Can be used to perform complex queries and joins.
Easy to setup, highly available, fault tolerant, and scalable.
Used when data is clearly defined.
Common use cases include online stores and banking systems.

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11
Q

What types of database engines does Amazon RDS support?

A
SQL Server.
Oracle.
MySQL Server.
PostgreSQL.
Aurora.
MariaDB.
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12
Q

What is Amazon’s proprietary database?

A

Amazon Aurora

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13
Q

Is RDS fully managed?

A

RDS is a fully managed service and you do not have access to the underlying EC2 instance (no root access).

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14
Q

What features does RDS include?

A

Security and patching of the DB instances.
Automated backup for the DB instances.
Software updates for the DB engine.
Easy scaling for storage and compute.
Multi-AZ option with synchronous replication.
Automatic failover for Multi-AZ option.
Read replicas option for read heavy workloads.

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15
Q

What is a DB instance?

A

A DB instance is a database environment in the cloud with the compute and storage resources you specify.

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16
Q

What options for encryptions are there in Amazon RDS?

A

You can encrypt your Amazon RDS instances and snapshots at rest by enabling the encryption option for your Amazon RDS DB instance.

Encryption at rest is supported for all DB types and uses AWS KMS.

You cannot encrypt an existing DB, you need to create a snapshot, copy it, encrypt the copy, then build an encrypted DB from the snapshot.

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17
Q

What is a DB subnet group?

A

A DB subnet group is a collection of subnets (typically private) that you create in a VPC and that you then designate for your DB instances.

Each DB subnet group should have subnets in at least two Availability Zones in each region.

It is recommended to configure a subnet group with subnets in each AZ (even for standalone instances).

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18
Q

How does AWS Charge for Amazon RDS?

A

DB instance hours (partial hours are charged as full hours).
Storage GB/month.
I/O requests/month – for magnetic storage.
Provisioned IOPS/month – for RDS provisioned IOPS SSD.
Egress data transfer.
Backup storage (DB backups and manual snapshots).

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19
Q

How well does Amazon RDS scale?

A

You can only scale RDS up (compute and storage).
You cannot decrease the allocated storage for an RDS instance.
You can scale storage and change the storage type for all DB engines except MS SQL.

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20
Q

How well does RDS cope in a disaster scenario?

A

RDS provides multi-AZ for disaster recovery which provides fault tolerance across availability zones:

  • Multi-AZ RDS creates a replica in another AZ and synchronously replicates to it (DR only).
  • There is an option to choose multi-AZ during the launch wizard.
  • AWS recommends the use of provisioned IOPS storage for multi-AZ RDS DB instances.
  • Each AZ runs on its own physically distinct, independent infrastructure, and is engineered to be highly reliable.
  • You cannot choose which AZ in the region will be chosen to create the standby DB instance.
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21
Q

How well does RDS provide Read Replicas?

A

Read replicas are used for read heavy DBs and replication is asynchronous.
Read replicas are for workload sharing and offloading.
Read replicas provide read-only DR.
Read replicas are created from a snapshot of the master instance.
Must have automated backups enabled on the primary (retention period > 0).

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22
Q

What is Amazon DynamoDB?

A

Amazon DynamoDB is a fully managed NoSQL database service that provides fast and predictable performance with seamless scalability.

23
Q

What are the features of DynamoDB?

A

Dynamo DB features and benefits:

NoSQL type of database (non-relational).
Fast, highly available, and fully managed.
Used when data is fluid and can change.
Common use cases include social networks and web analytics.

24
Q

What does Push Button Scaling mean?

A

Push button scaling means that you can scale the DB at any time without incurring downtime.

25
Q

What does SSD Based mean for Amazon DynamoDB?

A

SSD based and uses limited indexing on attributes for performance.

26
Q

What transport protocols and message serialization format does DynamoDB use?

A

DynamoDB is a Web service that uses HTTP over SSL (HTTPS) as a transport and JSON as a message serialization format.

27
Q

How many geographically distributed replicas does DynamoDB have?

A

Amazon DynamoDB stores three geographically distributed replicas of each table to enable high availability and data durability.

Data is synchronously replicated across 3 facilities (AZs) in a region.

28
Q

What does Cross Region replication allow?

A

Cross-region replication allows you to replicate across regions:

Amazon DynamoDB global tables provides a fully managed solution for deploying a multi-region, multi-master database.
When you create a global table, you specify the AWS regions where you want the table to be available.
DynamoDB performs all the necessary tasks to create identical tables in these regions and propagate ongoing data changes to all of them.

29
Q

What are some facts of DynamoDB?

A

Provides low read and write latency.

Scale storage and throughput up or down as needed without code changes or downtime.

DynamoDB is schema-less.

DynamoDB can be used for storing session state.

Provides two read models.

30
Q

What does Eventually Consistent Reads mean in DynamoDB?

A

Eventually consistent reads (Default):

The eventual consistency option maximizes your read throughput (best read performance).
An eventually consistent read might not reflect the results of a recently completed write.
Consistency across all copies reached within 1 second.

31
Q

What does Strong consistent reads mean in DynamoDB?

A

Strongly consistent reads:

A strongly consistent read returns a result that reflects all writes that received a successful response prior to the read (faster consistency).

32
Q

What is Amazon DynamoDB Accelerator?

A

Amazon DynamoDB Accelerator (DAX) is a fully managed, highly available, in-memory cache for DynamoDB that delivers up to a 10x performance improvement – from milliseconds to microseconds – even at millions of requests per second.

33
Q

What is Amazon Redshift?

A

Amazon Redshift is a fast, fully managed data warehouse that makes it simple and cost-effective to analyze all your data using standard SQL and existing Business Intelligence (BI) tools.

34
Q

What are the use cases of Amazon Redshift?

A

RedShift is a SQL based data warehouse used for analytics applications.

RedShift is a relational database that is used for Online Analytics Processing (OLAP) use cases.

RedShift is used for running complex analytic queries against petabytes of structured data, using sophisticated query optimization, columnar storage on high-performance local disks, and massively parallel query execution.

35
Q

What is Amazon Redshift ideal for?

A

RedShift is ideal for processing large amounts of data for business intelligence.

36
Q

How much faster is Redshift than traditional SQL DB?

A

RedShift is 10x faster than a traditional SQL DB.

37
Q

What is columnar data storage in Redshift?

A

RedShift uses columnar data storage:

Data is stored sequentially in columns instead of rows.
Columnar based DB is ideal for data warehousing and analytics.
Requires fewer I/Os which greatly enhances performance.

38
Q

What is advanced compression in Redshift?

A

RedShift provides advanced compression:

Data is stored sequentially in columns which allows for much better performance and less storage space.
RedShift automatically selects the compression scheme.

39
Q

What is the backup scheme like for Redshift?

A

RedShift uses replication and continuous backups to enhance availability and improve durability and can automatically recover from component and node failures.

40
Q

How many copies of data does Redshift keep?

A

RedShift always keeps three copies of your data:

The original.
A replica on compute nodes (within the cluster).
A backup copy on S3.

41
Q

What does continuous/incremental backups mean in Redshift?

A

RedShift provides continuous/incremental backups:

Multiple copies within a cluster.
Continuous and incremental backups to S3.
Continuous and incremental backups across regions.
Streaming restore.

42
Q

What failures does Redshift provide fault tolerance for?

A

RedShift provides fault tolerance for the following failures:

Disk failures.
Nodes failures.
Network failures.
AZ/region level disasters.

43
Q

What is Amazon ElastiCache?

A

ElastiCache is a web service that makes it easy to deploy and run Memcached or Redis protocol-compliant server nodes in the cloud.

44
Q

What benefits does in memory caching have in ElastiCache?

A

The in-memory caching provided by ElastiCache can be used to significantly improve latency and throughput for many read-heavy application workloads or compute-intensive workloads.

45
Q

What scenarios is ElastiCache best for?

A

Best for scenarios where the DB load is based on Online Analytics Processing (OLAP) transactions.

46
Q

What are some typical use cases for ElastiCache?

A

Web session store
In cases with load-balanced web servers, store web session information in Redis so if a server is lost, the session info is not lost, and another web server can pick it up

Database caching
Use Memcached in front of AWS RDS to cache popular queries to offload work from RDS and return results faster to users

Leaderboards
Use Redis to provide a live leaderboard for millions of users of your mobile app

Streaming data dashboards
Provide a landing spot for streaming sensor data on the factory floor, providing live real-time dashboard displays

47
Q

Where can ElastiCache’s EC2 nodes be accessed from?

A

ElastiCache EC2 nodes cannot be accessed from the Internet, nor can they be accessed by EC2 instances in other VPCs.

48
Q

What instances can ElastiCache be?

A

Can be on-demand or reserved instances too (but not Spot instances).

49
Q

What can ElastiCache do with session states?

A

ElastiCache can be used for storing session state.

50
Q

How many types of ElastiCache engines are there?

A

There are two types of ElastiCache engine:

Memcached – simplest model, can run large nodes with multiple cores/threads, can be scaled in and out, can cache objects such as DBs.

Redis – complex model, supports encryption, master / slave replication, cross AZ (HA), automatic failover and backup/restore.

51
Q

What is Amazon EMR?

A

Amazon EMR is a web service that enables businesses, researchers, data analysts, and developers to process vast amounts of data easily and cost-effectively.

52
Q

What framework does EMR use?

A

EMR utilizes a hosted Hadoop framework running on Amazon EC2 and Amazon S3.

Managed Hadoop framework for processing huge amounts of data.

53
Q

What other services does EMR support?

A

Also support Apache Spark, HBase, Presto and Flink.

54
Q

What is EMR commonly used for?

A

Most commonly used for log analysis, financial analysis, or extract, translate and loading (ETL) activities.