Section 14.123 High Availability

Question 1

High Availability

Answer 1

Aims to keep services continuously available by minimising downtime

● Achieved through load balancing, clustering, redundancy, and multi-cloud
strategies

Question 2

Uptime

Answer 2

The time a system remains online, typically expressed as a percentage

Question 3

Five nines

Answer 3

Refers to 99.999% uptime, allowing only about 5 minutes of downtime per year

Question 4

Some cloud based networks

Six nines

Answer 4

Refers to 99.9999% uptime, allows just 31 seconds of downtime per year

Question 5

How to maintain uptime

Load Balancing

Answer 5

Distributes workloads across multiple resources

■ Optimises resource use, throughput, and response time
■ Prevents overloading of any single resource
■ Incoming requests are directed to capable servers

Question 6

How to maintain uptime

Clustering

Answer 6

Uses multiple computers, storage devices, and network connections as a single system

■ Provides high availability, reliability, and scalability
■ Ensures continuity of service even in case of hardware failure
■ Can be combined with load balancing for robust solutions

Question 7

How to maintain uptime

Redundancy

Answer 7

Involves duplicating critical components to increase system reliability

■ Redundancy can be implemented by adding multiple:
● Power supplies
● Network connections
● Servers
● Software services
● Service providers

Prevents single points of failure in systems e.g Redundant power supplies

Question 7

Multi-Cloud Approach

Answer 7

Distributes data, applications, and services across multiple cloud providers

■ Mitigates the risk of a single point of failure
■ Offers flexibility for cost optimisation
■ Aids in avoiding vendor lock-in
■ Requires proper data management, unified threat management, and consistent policy enforcement for security and compliance

Question 8

Strategic Planning

Answer 8

Design a robust system architecture to achieve high availability

■ Utilise load balancing, clustering, redundancy, and multi-cloud approaches
■ Proactive measures reduce the risk of service disruptions and downtime costs
■ Safeguard organisational continuity and reliability in a competitive environment