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Virtualization terminology

As I read about virtualization and what it means in the Solaris and x86 world , there are many terminologies and acronyms that are vital to understanding the virtualization scenario. This is a list of some of the terms that I am reading about and it is a "growing" list, for sure. I will keep adding to this as I delve deeper into the x86 virtualization world.

• Virtualization – A way to abstract resources, whether software or hardware, so that applications running on it , are either unaware or need not be aware of the underlying hardware or software.Virtualization is not a "new" technology , by any means. However virtualization on x86 based systems has taken off in a big way relatively recently.

• Paravirtualization -  A virtualization technique where "guest" OSes are "modified" in some way to increase performance on x86 systems when they are run in a virtualized environment.

•  Hypervisor – It is also called a Virtual Machine Monitor (VMM),which allows multiple "guest" operating systems to run simultaneously on a
  “host” OS. A good example of a hypervisor is Xen.

• Xen – Xen is an open source project that virtualizes the hardware allowing multiple Oses to run simultaneously on a single piece of hardware. The Xen project is available on x86 and x64 based systems. For more information see the Xen community page on the OpenSolaris page. Go here to read about Xen for OpenSolaris developers.
  

• Dom0 - Short for Domain 0 . An OS that runs Xen as a "host" OS. The operating system that "hosts" the virtualization software is called the "host" OS. "Host OS" is a more generic term, whereas Dom0 is specific to Xen.
  

• DomU - Short for Unprivileged domain. An OS that runs as "guest" under Xen.  The general term is "guest OS" which is the OS that runs inside a virtualization software.
  

• Zones/Solaris Containers - It is a virtualized operating system in OpenSolaris that emulates an OS instance. It runs on SPARC and x86. Zones virtualize the OS allowing multiple OS instances to run on one Solaris kernel.Zones provide an isolated, secure environment to run multiple applications or even multiple instances of the same application.
  

• BrandZ - Branded Zones, or BrandZ, is the underlying framework that allows us to create non-native zones on a machine running the Solaris Operating System. Xen is a technology that virtualizes an entire machine, allowing you to run a complete operating system including the kernel. BrandZ allows you to run just an operating system's userspace components,with a Solaris kernel under the hood. Branded Zones are available from Solaris 10 8/07 release onwards.
  

• SCLA – Short for Solaris Containers for Linux Applications ; lx brand.From OpenSolaris - Solaris Containers for Linux Applications (SCLA) uses the BrandZ technology to run Linux applications on the Solaris Operating System . Linux applications run unmodified in the secure environment provided by the Solaris Container feature. This runs on x86 and x64 machines.
  

• LDOMs - Short for Logical Domains. From BigAdmin : "LDoms technology is part of a suite of methodologies for consolidation and resource management that includes Sun Fire Dynamic System Domains and Solaris OS Containers, of which resource
  control and operating system virtualization are a subset. This technology allows the user to allocate a system's various resources, such as memory, CPUs, and devices, into logical groupings and create multiple, discrete systems, each with their own operating system, resources, and identity within a single computer system. "
  

Posted at 01:03PM Sep 17, 2007 by Jyothi Srinath in Sun  |  Comments[5]