What is Redundancy?
In previous blogs we’ve talked about various ways to try and prevent IT disasters in your small business.
We’ve explained the differences between backup, disaster recovery and business continuity but when it comes down to disaster prevention a term we often use is redundancy. But what does this actually mean in an IT context and how does it differ to things like backup and disaster recovery.
We explain all…………….
What is meant by redundancy?
Redundancy is an engineering term which means “the duplication of critical components or functions of a system with the intention of increasing reliability of the system, usually in the form of a backup or fail-safe, or to improve actual system performance”
In many safety-critical systems, such as hydraulic systems in aircraft, some parts of the control system may be triplicated, which is formally termed triple modular redundancy (TMR).
What does redundancy mean in an IT context?
In computer science the there are four major forms of redundancy, these are:
When we talk about building redundancy into an infrastructure project, we will most likely be referring to hardware redundancy.
Hardware redundancy simply means adding a duplicate device or component within the system that steps in when a primary device or component fails. The goal is to ensure zero downtime.
The term redundancy is used because if everything is working correctly the duplicate device or competent does nothing, and is therefore redundant.
Hard drives are the most common form of redundancy. A simple set up would have a primary drive copied on a regular basis to a backup drive. If the primary drive fails, the secondary drive could be slotted in. The only data lost will be anything produced since the last time the files were copied.
Within businesses with a server a RAID configuration can be used to mirror data across two drives in real time.
In some businesses the computing environment includes server redundancy. To enable this, a server replica is created with the same computing power, storage, applications and other operational parameters.
A redundant server is kept offline. That is, it powers on with network/Internet connectivity but is not used as a live server. In case of failure, downtime or excessive traffic at the primary server, a redundant server can be implemented to take the primary server’s place or share its load.
This is a obviously a brilliant disaster recovery option, however it doubles the cost of your server solution in the first place, and doubles your running costs. Plus you need the space for two servers. This is generally impractical and overkill for the majority of businesses.
Network redundancy is a process through which additional or alternate instances of network devices, equipment and communication mediums are installed within network infrastructure. It is a method for ensuring network availability in case of a network device or path failure and unavailability. As such, it provides a means of network failover.
Network redundancy is primarily implemented in enterprise network infrastructure to provide a redundant source of network communications. It serves as a backup mechanism for quickly swapping network operations onto redundant infrastructure in the event of unplanned network outages.
Typically, network redundancy is achieved through the addition of alternate network paths, which are implemented through standby routers and switches. When the primary path is unavailable, the alternate path can be instantly deployed to ensure minimal downtime and continuity of network services.
One form of network redundancy is Multi-Wan, which is available through some firewalls such as the WatchGuards that we at Your IT provide. Multi-Wan provides the ability to have multiple internet connections into a single site. If one internet connection goes down you simply switch to another giving a continuous connection.
Again, cost is the consideration. Doubling, or even trebling, the cost of your internet connection is probably not worth it for the majority of businesses with a reliable internet connection as downtime would be minimal anyway.
Building redundancy into your IT solution is an effective way of minimising downtime, and enables fast, effective disaster recovery.
However, the benefits need to be balanced with the level of risk and the often-considerable costs.
There is no one ‘right’ method or level of redundancy. Understanding the businesses budgets, needs and risks is key to providing the right levels of redundancy in a cost-effective way.
How we can help
At Your IT Department we’ve helped over 120 clients build and develop their IT infrastructure and systems. As our clients outsourced, but fully integrated, IT partner we work hard to understand our clients businesses and design solutions that meet their needs.
So, give us a call on 0115 8220200 or fill in the contact form for a free informal chat about your IT systems and how we can build redundancy into them.
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