How can you create redundancy in a data center design?

Drive Mirroring is common for redundant systems. Drive stryping on SCSI Backbone Servers is also common for more reliable redundance. Always have a Didaster Plan ready.

Incorporating redundancy into a data center's design includes a multi-layered approach where every critical system has a reliable backup. Automated power sources with immediate failovers, robust cooling systems with extra units, diverse ISP connections, RAID-configured storage, and virtualized server clusters are foundational. To this infrastructure, advanced sensors are added to continuously monitor room temperature and power usage. These sensors play a pivotal role in preventive maintenance, instantly flagging any anomalies that could indicate potential system failures, allowing for preemptive action to maintain operational integrity and prevent downtime.

In data center design, cooling redundancy is achieved by deploying multiple, strategically placed cooling units and leveraging advanced methods like liquid cooling and free cooling. This system ensures that if one unit fails, others maintain the necessary temperatures. Sensor integration allows for continuous monitoring and automatic adjustment, optimizing the environment and preemptively addressing potential issues.

Network redundancy in a data center is crafted by intertwining a variety of cabling techniques and protocols to ensure uninterrupted service. Utilizing redundant cabling, such as diverse fiber paths and structured cabling systems, along with Spanning Tree Protocol (STP) to prevent loops, helps maintain continuous network availability. Failover protocols like HSRP or VRRP, alongside multiple ISPs, create a network that swiftly adapts, rerouting traffic to operational links during an outage, preserving critical connectivity.

RAID 5 is the most commonly used RAID level as it optimizes read/write performance, effective storage capacity and single hard disk drive fault tolerance with data and parity data striped or evenly distributed across at least three HDDs. A faulty HDD can be hot swapped without downtime and rebuilt automatically from the other HDDs data and parity data based on the binary XOR function. Data cannot be reconstructed in case of concurrent failure of more than one HDD. This is the main risk to be weighed against the advantages of RAID 5.

Beyond the traditional pillars of data center redundancy, one aspect that is often overlooked is 'geographical redundancy.' Many organizations focus on intra-facility redundancy but may neglect inter-facility planning. By distributing your data center architecture across different geographic locations, you can mitigate the risks posed by regional power outages, natural disasters, or even man-made events that could affect a single site.

People redundancy Most of the time we specialized our resources in specific activity of the Datacenter. It is critical to have minimum two people mastering the overall achitecture of the Datacenter and be able to articulate it clearly. It reduce the risky of depency on a single human. It is also important to replicate that knowledge in all critical nodes like power, cooling, network or physical servers. Specially for huge Datacenters with many levels of management.