Mirroring involves having a duplicate of your systems that acts as both a back-up and a means of providing continuity if your systems went down. There are several different methods of mirroring, ranging from a server with an identical configuration to your own but with no data on it (known as ‘bare metal’), to a full duplicate in real-time where everything is the same.
Service can be seamless with a full mirroring approach, providing location is not an issue. So you might have a mirrored server in a separate location with independent links into your system, so that you could switch over to it if needed.
Virtualisation is a form of mirroring that offers a significant extra benefit. It reduces the processing power needed on any one piece of equipment, therefore reducing the likelihood of its performance deteriorating. It does this because a separate, physical, identical server is not required as it is with other full mirroring approaches. Instead, a combination of hardware and software systems are used to create a ‘virtual’ server (hence the name), rather than a physical object duplicating what you already have.
This combination of hardware and software brings with it an extra layer of complexity and cost that might not exist with other mirrored applications, so the cost-benefit equation needs to be looked at. But for organisations that need seamless continuity, it is a solution that provides additional benefits.
As with many other aspects of developing your IT, speak to a reliable IT Support organisation with expertise in the area, if seamless business continuity is an area you would like to investigate.