Question 1

What is caching?

A global network for content distribution
An in-memory database
A high-speed data storage layer
A way to store passwords

Question 2

Which type of data should you cache?

Dynamically generated web content
Static data that is frequently accessed
Data that can be retrieved quickly with simple queries
Specialized data that is needed by a subset of users

Good candidates for caching include data that does not change often and that users access frequently.

Question 3

Which is a benefit of caching?

Decreased costs
Reduced response latency
Increased application reliability
Load balancing the application

Caching reduces response latency by reducing or eliminating slow resources between the requester and the content. It can reduce network hops, eliminate the need to communicate over slow links or through slow devices, or reduce load on the origin.

Question 4

Which types of content on a web page can be cached using an edge cache? (Select TWO.)

Dynamically generated content, such as a user’s name
User-generated data, such as search terms entered by user
Web objects, such as hyperlinks
Shopping cart filled with a user’s item
Video files, such as a product demo

An edge cache can cache static content. Such content might include web objects (for example, HTML documents, CSS style sheets, or JavaScript files), image files, and video files.

Question 5

What does Amazon CloudFront enable?

Automatic creation of a time to live (TTL) value
Bidirectional caching between users and an origin host
Transactional processing with an in-memory database
Multi-tiered and regional caching of content

CloudFront provides a multi-tiered cache so that you can have multiple rules for when content expires. It also provides Regional caching, which reduces latency by reducing the number of network hops.

Question 6

How does Amazon CloudFront use edge locations?

It caches local content at edge locations. It delivers the cached content to clients through the edge location that requires the fewest network hops to reach those clients.
It caches Regional data at Regional edge locations and delivers the content to clients through their Regional edge locations.
It caches frequently accessed content at edge locations. It delivers the cached content to clients through the edge location with the lowest latency to those clients.
It caches all content from an origin distribution at the edge location and delivers the content to clients through the fastest edge location.

The requested content might be part of a CloudFront distribution and unavailable at the edge location. In this case, CloudFront fetches the content from the origin and then caches it at the edge location.

Question 7

Which statement describes an efficient way to deliver on-demand video content?

Use Amazon S3 to store and serve the content.
Launch an Amazon EC2 instance to host and serve your video content.
Launch an Amazon EC2 instance to host your video content. Then use Amazon CloudFront to deliver the content.
Use Amazon S3 to store the content. Then use Amazon CloudFront to deliver the content.

Storing content in Amazon S3 and then delivering it near the end user by using Amazon CloudFront is an efficient way to deliver on-demand video content.

Question 8

Which role does Amazon CloudFront play in protecting against distributed denial of service (DDoS) attacks?

Routes traffic through edge locations
Controls traffic by the source IP addresses of requests
Performs deep packet inspection to detect attacks
Restricts traffic by geography to help block attacks that originate from specific countries

DDoS attacks place a large distributed load on concentrated points. With CloudFront, you can route traffic through edge locations to reduce the load on individual systems.

Question 9

How can an application use Amazon ElastiCache to improve database read performance? (Select TWO.)

Write data to ElastiCache whenever the application writes to the database.
Read data from the database first, and write the most frequently read data to ElastiCache.
Read data from ElastiCache first, and write to ElastiCache when a cache miss occurs.
Direct all read requests to the database, and configure it to read from ElastiCache when a cache miss occurs.
Replicate the database in ElastiCache, and direct all reads to ElastiCache and all writes to the database.

Writing data to the cache only when a cache miss occurs is called lazy loading. Writing data to the cache every time that the application writes data to the database is called write-through.

Question 10

Which type of caching strategy should be used when there’s data that must be updated in real time?

Lazy loading
Time to live (TTL)
Cache-control headers
Write-through

A write-through caching strategy is used when you have data that must be updated in real time. Caching strategies for Memcached

CLD120 Module 12 Knowledge Check

Caching Content

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