What would you do for fault tolerance and load balancing?
Select one:
a. Host your application replicas at multiple availability zones within the same region
b. Host your application replicas in distant regions
c. Both of the above
d. Load balancing and fault tolerance is automatically provided by cloud service providers
The correct answer and explanation is:
The correct answer is c. Both of the above.
Fault tolerance and load balancing are critical for ensuring that applications remain operational and responsive even in the event of system failures or high traffic. The best practices for achieving both rely on distributing resources across multiple regions and availability zones.
Fault tolerance refers to the ability of a system to continue operating smoothly even in the face of hardware or software failures. Hosting application replicas in multiple availability zones within the same region, as mentioned in option a, is one approach to fault tolerance. By doing so, if one availability zone experiences an issue, the application can still operate from another zone without affecting service continuity. However, relying solely on a single region may not be sufficient for handling large-scale regional failures, such as data center outages or natural disasters.
On the other hand, option b suggests hosting replicas in distant regions, which enhances fault tolerance further by protecting against even larger-scale failures that could impact an entire region. If one region faces a problem, the application can still be accessed and operated from another geographically distant region.
Combining both approaches—hosting application replicas in multiple availability zones within a region and in distant regions—ensures the application can withstand failures at various levels, including both local and regional. This approach is known as a multi-region, multi-availability zone architecture, which is widely adopted in cloud environments to achieve both fault tolerance and load balancing.
While some cloud service providers offer automatic load balancing and fault tolerance features, these features are more effective when coupled with a distributed architecture across multiple zones and regions, as they ensure resilience and scalability. Therefore, option d is incorrect because load balancing and fault tolerance must still be actively configured to maximize availability and performance.