# Overview of Redundant Systems

> URL: https://www.atlantic.net/about-us/whitepapers/overview-of-redundant-systems/ | Updated: 2026-09-16

Redundancy in computing and networking is crucial for supporting business continuity and preventing downtime. This whitepaper explores various types of redundant systems and their implementations across hardware and software services.

## Key topics covered

- Types of redundant systems: Active-Inactive (Hot-Cold), Active-Active (Hot-Hot), and Active-Standby (Hot-Warm) configurations, each with unique approaches to maintaining system uptime.

## Examples of redundant software services

- Hyper-V Replica: a hot-warm redundancy solution for virtual machines, enabling replication of primary VMs to a separate physical host for failover protection.
- Hyper-V clustering: clustering VMs on a single host for local redundancy and load balancing through virtual networking.
- HAProxy: a Linux-based load balancer and high-availability solution for TCP and HTTP-based applications.

## Examples of redundant hardware services

- RAID (Redundant Array of Independent Disks): different RAID levels (RAID 0, RAID 1, RAID 5, RAID 10) for data protection and increased disk I/O performance.
- Networking redundancy: First Hop Redundancy Protocols (FHRP) like VRRP, HSRP, and GLBP for redundant gateways and load balancing.
- Data center redundancy: the Uptime Institute's tiered classification system for data center fault tolerance and high availability.

## Download this helpful guide to:

- Understand the importance of redundancy in maintaining system availability.
- Learn about different types of redundant systems and their applications.
- Explore examples of redundant software and hardware services.
- Gain insights into data center redundancy and tiered classifications.