Building Robust Infrastructures: Data Center Redundancy Strategies

Any disruption to data center operations typically leads to disruption across the business as a whole. To protect against this, data centers are designed with resilience in mind. In particular, they implement high levels of redundancy. Here is a quick guide to what you need to know about data center redundancy strategies.

Understanding data center redundancy

The term “data center redundancy” refers to the implementation of backup systems and components within a data center’s infrastructure to ensure continuous operation. It involves duplicating critical infrastructure components and implementing mechanisms that can seamlessly transfer workloads between them in the event of a failure.

In managed data centers, such as colocation facilities, the effective use of redundancy is often key to being able to offer and achieve a compelling uptime guarantee. Currently, the industry standard is 99.999% uptime or better. Some data center providers even offer a 100% uptime guarantee.

Data center redundancy strategies

Data center redundancy strategies typically have to cover hardware, network connectivity, and data. In private data centers and cloud data centers, the data center redundancy strategies will be handled entirely by the business or vendor respectively.

In colocation facilities, responsibility will usually be divided between the vendor and the client. The colocation vendor will take responsibility for the shared infrastructure and anything needed to run it. Clients will take responsibility for their own equipment and data.

Data center redundancy strategies for hardware

Hardware can be roughly divided into two categories. These are infrastructure-related hardware components and workload-related hardware components. The redundancy strategies are much the same for both types. There may, however, be a difference in who takes ownership of them.

Hardware redundancy can be achieved in one or both of two main ways. The first way is by straightforward replication. This is the standard approach in workload-related hardware components. For example, if one storage drive fails, it will simply be swapped out for another storage drive, generally on a like-for-like basis.

The second way is by means of solutions that produce the same or a similar result but in different ways. This is more common with infrastructure-related hardware. For example, if there is a power outage, data centers will generally fall back on uninterruptible power supplies (UPS) as their immediate solution. If the power outage continues, however, they will move on to fuel-powered generators.

Data center redundancy strategies for networking

Ensuring network redundancy requires more than just ensuring hardware redundancy. Here are three additional measures data centers need to implement.

Multiple internet service providers (ISPs)

Data centers connect to multiple ISPs through diverse paths to maintain internet connectivity even if one provider experiences downtime. They implement Border Gateway Protocol (BGP) routing protocols to route traffic dynamically through the most reliable paths. Reliability is calculated based on factors such as latency, bandwidth, and AS path length.

Redundant network paths

Redundant network paths are established within data center architectures to maintain connectivity in the event of link failures or congestion. Technologies such as Spanning Tree Protocol (STP) and link aggregation (LAG) enable the implementation of redundant network paths. STP prevents loops in network topologies by blocking redundant links and activating them only when the primary link fails. LAG combines multiple physical links into a single logical link to increase bandwidth and provide redundancy.

Geographic redundancy

Geographic redundancy involves distributing data center resources across multiple geographical locations to mitigate the risk of localized disasters. Replicating data and services in geographically diverse regions ensures business continuity and disaster recovery capabilities. Advanced technologies like global load balancing and Domain Name System (DNS) failover facilitate seamless failover between geographically redundant data centers.

Data center redundancy strategies for data

Data is, literally, the reason why data centers exist. Implementing effective redundancy strategies is, therefore, key to data center operations. Here are three measures data centers typically implement.

RAID (Redundant array of independent disks)

A Redundant array of independent disks is a storage technology that combines multiple physical disks into a single logical unit to improve performance, reliability, or both. RAID configurations such as RAID 1 (mirroring), RAID 5 (striping with parity), and RAID 6 (dual parity) offer different levels of redundancy and fault tolerance.

Data mirroring

Data mirroring involves creating identical copies of data on separate storage devices or systems in real time. Any changes made to the primary data are mirrored to the secondary storage, ensuring consistency and redundancy. Data mirroring provides instantaneous failover capabilities and protects against disk failures, enabling continuous access to data without interruption.

Erasure coding

Erasure coding is a technique used to achieve data redundancy and fault tolerance by encoding data with additional parity information and distributing it across multiple storage devices. Erasure-coded data can withstand the loss of individual disks or data chunks, allowing data centers to maintain data integrity and availability even in the face of multiple failures.