Virtual Appliances can be virtual machines that have been built to perform a specific function. The operating system and other software needed to perform this has already been installed. The virtual machine can then be shared and deployed as needed. Examples include backup servers (to perform data deduplication), enterprise LAMP servers, or email servers (and spam filtering). Virtual appliances are everywhere. Many are free to use and require little or no setup or maintenance. For more info… http://www.vmware.com/appliances/ http://virtualappliances.net/ http://www.turnkeylinux.org/ Storage virtualization is the separation of the logical storage from the physical device/media. This is commonly used to aggregate the space available from a heterogeneous mixture of storage devices (possibly from different hardware vendors). Memory virtualization is similar to Storage virtualization, where the memory pool that is made available to one or more computer systems can be physically located on the RAM installed in multiple machines. This can then be shared across the systems as needed. Platform or Full virtualization is commonly achieved by using software to emulate the physical computer hardware. This can be used to run a variety of Operating Systems, and any software needed can be installed and runs within the virtual machine.
For Server Consolidation, there are industry guidelines that suggest it is possible to run up to 100 virtual machines per physical server. This depends on the load that would be placed on the physical hardware. Server consolidation is rapidly being applied to enterprise datacenters, where hundreds of physical servers are being converted to virtual machines. This has the effect of dramatically reducing the power consumption and cooling requirements for the installation Full virtualization can be used in any situation where there is a desire to share a computer resources among many users, and there is a need for the sharing to occur in isolation for security and reliability.
Most virtualization software includes the ability to take “snapshots” of the virtual machine. These can be used to recover from a test failure, or to restore the machine to a known state when the testing has been completed. Usually, multiple snapshots are supported and a graphical UI is available to allow the user to start the VM from any desired point.
There are many platform virtualization solutions available. Comparison pages such as this one on Wikipedia help to sort out the most appropriate one to use for your needs and situation. http://en.wikipedia.org/wiki/Comparison_of_platform_virtual_machines There are also “bare metal” virtualization solutions available. Examples of these include Xen (www.xen.org), and Microsoft Hyper-V (requires Windows Server 2008). Bare metal solutions (hypervisors) are designed to be the first software installed on the physical platform. The hypervisor is then used to partition the hardware resources so they can be used by one or more virtual instances.
VirtualBox is freely available as open source software under the GNU General Public License (GPL). Since it is free, there is no reason not to give it a try. However, before you install any software on a “work” computer – check with your IT department to ensure this does not violate any company policies. They may also be able to give some help with VM configuration to enable them to work on your network, or on a separate sub-network.
![Overview ,[object Object],[object Object],[object Object],[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)