High Availability Solutions

In the realm of IT operations, High Availability refers to a system (such as a network, a server array, or cluster) that is designed to prevent service loss by managing and reducing failures while minimizing planned downtime.

High availability is crucial in situations where life, health, well-being, and economic stability are at risk. In information technology, system or component availability is typically expressed as a percentage of yearly uptime. Service Level Agreements (SLAs) often use these availability percentages for billing calculations. The goal of achieving the highest levels of service availability is often referred to as "five nines" – 99.999% availability – although achieving 100% availability is considered unachievable.

High Availability Management
Achieving high availability requires thorough planning and consistent monitoring.

To begin high availability planning, identify services critical for business continuity and those that should be available. Determine the extent to which the organization is willing to go to ensure availability, based on budget, staff expertise, and tolerance for service outages.

- Network availability: Monitor network availability compared to the SLA with your Internet Service Provider (ISP) using Network Internet Control Message Protocol (ICMP) echo pings or network monitoring software.
- Bandwidth usage: Analyze bandwidth consumption during peak and idle times to plan bandwidth allocation and avoid inadequate bandwidth scenarios.
- HTTP availability and visibility: Monitor internal and ISP HTTP requests to detect early warning signs of problems and ensure users can access your service.
- System availability: Keep track of abnormal and normal system shutdowns for operating systems, databases, and enterprise servers.
- Performance metrics: Monitor the number of users, latency of requests, historical CPU utilization, disk capacity, I/O throughput, fiber channel controller, switch bandwidth, system memory usage, and group servers by function to ensure optimal performance.