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Home > Resources > Technical Resources > Black Box Explains > KVM > Virtualisation vs. KVM

Virtualisation vs. KVM Switching

Benefits of Virtualisation

Disadvantages of Virtualisation

  • Provides high availability for critical applications - Automated migration of servers in case of hardware failure.
  • Responds faster to changing business demands.
  • Reduces power consumption and server maintenance costs.
  • Improves disaster recovery options – Remote replication of servers.
  • Ease of management of the virtual environment – One piece of software manages everything.
  • Ability to run multiple platforms/operating systems - SUN, Linux, Unix, Windows Server.
  • Can be supported by KVM solutions for server management and remote access.
  • Initial set up can be a costly exercise – Cost of servers, software and licensing to run VM.
  • Can be unsuitable for processor intensive applications.
  • Main Domain Controllers should be physical discrete servers, with a only a replicated version virtualised. If the virtual server is down, no authentication can take place via AD.
  • A single server failure will bring down multiple applications however the high availability feature of virtualisation will counter this if properly set up.
  • Unidirectional move down a particular vendors path – Difficult to change vendors once set up.

Benefits of KVM Switching

Disadvantages of KVM Switching

  • Established technology.
  • Cost effective.
  • Provides an out of band absolute access solution – Even if the entire network is lost, KVM access will continue to function being completely network independent and utilising its own hardware platforms.
  • A single server failure has no effect on other applications or servers.
  • Instantaneous switching between hundreds or thousands of servers.
  • Support of full HD video providing pixel perfect video images.
  • Integrated power control for reboot of servers.
  • Fully compatible with Virtualisation and can expand and compliment access solutions.
  • More hardware required when adding further servers.
  • Does not reduce consumption; in fact the extra KVM hardware will require additional power.

Ideal Scenario for Virtualisation

Ideal Scenario for KVM Switching


  • Existing servers are under-utilised and have plenty of spare processing power.
  • Power consumption is a major issue.
  • Reducing power consumption is a major goal.
  • Real estate is costly and space saving is a major concern.
  • High availability is required.
  • Disaster recovery needs to be fast, accurate and reliable.


  • Access to servers is required 24/7 without fail .
  • Software solution cannot be relied upon in network disaster scenarios.
  • Loss of a server can cause loss of revenue or loss of essential services.
  • RAID arrays are used to host the actual virtualised servers. These sit behind the virtualised machines.
  • Trading floors and investment houses require reliable instantaneous switching.

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