High Availability (HA) ...the System's ability to remain operational & accessible with minimal downtime.

 

High Availability (HA)

High Availability (HA) refers to a system's ability to remain operational and accessible with minimal downtime, even in the event of hardware or software failures.

 Key Characteristics of High Availability:

1. Redundancy:
   Duplicate components (servers, databases, load balancers) to eliminate single points of failure.
2. Failover:
   Automatic switching to a standby system or component when the primary fails.
3. Health Checks and Monitoring:
   Constant checks to detect failures and trigger recovery actions.
4. Load Balancing:
   Distributes traffic across multiple servers to prevent overload and ensure continued service.
5. Data Replication:
   Keeps data synchronized across different nodes or data centers.

twtech Examples in Cloud Environments:

• AWS:
• EC2 instances spread across multiple Availability Zones (AZs).
• RDS with Multi-AZ deployment for automatic failover.
• Elastic Load Balancer (ELB) to distribute traffic.
• Kubernetes:
• Replication controllers/pods across multiple nodes.
• Self-healing via probes and restart policies.

 High Availability vs. Other Concepts:

Concept	Purpose
High Availability	Minimizes downtime and ensure uptime
Scalability	Handles increased load or traffic
Elasticity	Automatically scale up/down with demand
Fault Tolerance	Continues operation despite faults