Chapter 16 Optimization

Question 1

5 pillars

Answer 1

• operational excellence
• security
• reliability
• performance efficiency
• cost optimization

Question 2

Cost Tagging Categories

Answer 2

1. Environment
2. Application ID
3. Automation (opt in/out)
4. Business Unit
5. Owner

Question 3

How to enforce tagging?

Answer 3

Via IAM policy which specified required tag names.

Question 4

Why would you potentially be charged for stopped EC2 instance?

Answer 4

Because an associated EBS volume was not terminated.

Question 5

Are you charged for an unused Elastic IP address?

Answer 5

Yes, but it is not charged if it is attached to an EC2 instances.

Question 6

General purpose instance types

Answer 6

A1, T2, M3, M4

Question 7

Compute Optimized instance types

Answer 7

C3, C4

Question 8

Memory Optimized instance types

Answer 8

X1, R3, R4

Question 9

Storage Optimized Instance Types

Answer 9

I3, D2

Question 10

Accelerated Computing Instance Types

Answer 10

P2, G3, F1

Question 11

Reserved instance duration

Answer 11

1-3 years, potential savings of 75%

Question 12

For DB reserved instances, what happens when you exceed reserved rate?

Answer 12

You are charged the on demand rate.

Question 13

Termination notices for spot instances are issues when?

Answer 13

2 minutes before instances are terminated

Question 14

How to guarantee a specific time duration with Spot instances?

Answer 14

Use block durations, which is a parameter set when using spot instances. It guarantees a duration block.

Question 15

How to minimize impact of interruptions with Spot instances?

Answer 15

Persist data with EBS volume and/or split up the work using SQS.

Question 16

______refers to the functionality that automatically replaces unhealthy instances in your application, maintains your fleet at the desired capacity, and balances instances across Availability Zones.

Answer 16

Fleet management

Question 17

A _______ is a snapshot of a particular state of a resource, such as an Amazon EC2 instance, Amazon EBS volumes, and an Amazon RDS DB instance.

Answer 17

golden image

Question 18

If you don’t want to make manual predictions for an auto-scaling group, what can you use?

Answer 18

predictive scaling. It leverages machine learning algorithms

Question 19

Aurora auto scaling is available for MySQL and Postgres, but Aurora serverless is available only for _____

Answer 19

MySQL

Question 20

How does Lambda scale?

Answer 20

It runs multiple, parallel functions

Question 21

Glacier vs Glacier Deep Archive

Answer 21

Deep archive is 7-10 year data retention for compliance purposes. 12 hr retrieval time (vs minutes to several hrs for Glacier)

Question 22

When to use S3 vs EFS?

Answer 22

S3 as much as possible to keep storage costs low, and EFS when your application requires it.

Question 23

What tool allows you to analyze access patterns for S3 data and allow you to transition objects to the appropriate storage class?

Answer 23

Amazon S3 Analytics: Storage Class Analysis

Question 24

Tool which allows you to create CSV with replication and encryption status of S3 objects on weekly or monthly bases?

Answer 24

S3 Inventory

Question 25

S3 can publish storage, request, and data transfer metrics to _____

Answer 25

CloudWatch

Question 26

If you have S3 objects in csv format, how can you select just a subset of the data in the object?

Answer 26

using S3 Select. Drastic performance increase btw.

Question 27

How to query archived data?

Answer 27

Glacier Select (seems to return entire object?)

Question 28

For EBS, to achieve best performance consistently, use ___

Answer 28

EBS optimized instances

Question 29

When I/O is more important than fault tolerance, use a ______ configuration

Answer 29

RAID 0

Question 30

Important Metrics for EBS

Answer 30

BurstBalance and VolumeQueueLength (among others)

Question 31

If EBS volume in unattached, it is marked as _____

Answer 31

available

Question 32

For a general purpose SSD, optimize for ____ so that you only pay for what you use.

Answer 32

capacity

Question 33

S3 Transfer Acceleration leverages ____ to improve application-client transfer speeds

Answer 33

Cloudfront/edge locations

Question 34

DAX

Answer 34

DynamoDB Accelerator. Memory cache for DynamoDB which offers performance optimization. Best for when you have predictable loads. (note that auto scaling best for unpredictable loads)

Question 35

How to enable versioning in DynamoDB?

Answer 35

Use a versionId as the sort key with prefix of 0. Whenever you update an item, make two copies, one which is the actual version ID and one which will overwrite the item with versionId of 0.

Question 36

Do you want more or less indexes in DynamoDb? Why?

Answer 36

Less, additional indexes (which aren’t used often) contribute to costs and degrade I/O without improving application performance.

Question 37

Why should you be careful about attribute projections in DynamoDB?

Answer 37

If you update an attribute that is projected in an index, you incur the cost of updating the index as well.

Question 38

What are sparse indexes in DynamoDB?

Answer 38

An index in which the sort key is not present in every item of the table. This allows queries of a subset of the table items, and results in faster, less expensive results. (i.e. CustomerId & OrderID)

Question 39

RI Utilization report shows how much you 1. _______ while RI Coverage report shows how much you 2.______

Answer 39

1. over purchased

2. under purchased

Question 40

Most granular analysis of costs provided by ____

Answer 40

AWS Cost and Usage Report

Question 41

What service allows you to stop/terminate EC2 instances which have been underutilized/unused for too long and/or stop instances which have EBS as root volume?

Answer 41

CloudWatch

Question 42

EBS volumes should be attached to what type of instance?

Answer 42

EBS Optimized instance

Question 43

What metric would you look at to determine if your provisioned IOPS is sufficient for your application?

Answer 43

VolumeQueueLength