Global server load balancing (GSLB) in HLD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Global Server Load Balancing (GSLB)?

GSLB is a method to distribute user requests across multiple data centers worldwide to improve availability, reduce latency, and balance traffic load.

intermediate

Name two common techniques used by GSLB to direct traffic.

1. DNS-based redirection, where DNS responses guide users to the best server.<br>2. Anycast routing, where the same IP is advertised from multiple locations and routing directs users to the nearest server.

beginner

Why is health checking important in GSLB?

Health checks monitor server and data center status to avoid sending traffic to unavailable or slow servers, ensuring reliability and good user experience.

intermediate

What role does latency measurement play in GSLB?

Latency measurement helps GSLB choose the server closest or fastest to the user, reducing response time and improving performance.

beginner

Explain the difference between local load balancing and global server load balancing.

Local load balancing distributes traffic within a single data center or region, while GSLB distributes traffic across multiple geographic locations worldwide.

Which method is commonly used by GSLB to direct users to the nearest data center?

A Round-robin scheduling

B Session replication

C Sticky sessions

D DNS-based redirection

DNS-based redirection allows GSLB to respond with IP addresses of the closest or best-performing data center.

What is the main purpose of health checks in GSLB?

A To monitor server availability and performance

B To encrypt user data

C To cache static content

D To balance load within a single server

Health checks ensure traffic is only sent to healthy and responsive servers.

Which of the following is NOT a benefit of GSLB?

A Improved fault tolerance

B Automatic code deployment

C Reduced latency

D Traffic load distribution across regions

Automatic code deployment is unrelated to GSLB functionality.

Anycast routing in GSLB means:

A Multiple servers share the same IP address advertised from different locations

B Servers use different IP addresses for each user

C Traffic is routed randomly

D Servers replicate session data

Anycast allows routing to the nearest server advertising the same IP.

Which factor is NOT typically considered by GSLB when choosing a server?

A Server health

B User location latency

C Server CPU temperature

D Current server load

Server CPU temperature is not a standard metric for GSLB decisions.

Describe how Global Server Load Balancing improves user experience across multiple data centers.

Think about how spreading traffic worldwide helps users get faster and more reliable service.

Explain the main techniques GSLB uses to decide where to send user requests.

Consider how GSLB knows which server is best for each user.