Archive for September 29th, 2010

Paravirtualization – Wikipedia, the free encyclopedia

Paravirtualization – Wikipedia, the free encyclopedia.


In computing, paravirtualization is a virtualization technique that presents a software interface to virtual machines that is similar but not identical to that of the underlying hardware.

The intent of the modified interface is to reduce the portion of the guest’s execution time spent performing operations which are substantially more difficult to run in a virtual environment compared to a non-virtualized environment. The paravirtualization provides specially defined ‘hooks’ to allow the guest(s) and host to request and acknowledge these tasks, which would otherwise be executed in the virtual domain (where execution performance is worse.) Hence, a successful paravirtualized platform may allow the virtual machine monitor (VMM) to be simpler (by relocating execution of critical tasks from the virtual domain to the host domain), and/or reduce the overall performance degradation of machine-execution inside the virtual-guest.

Paravirtualization requires the guest operating system to be explicitly ported for the para-API — a conventional O/S distribution which is not paravirtualization-aware cannot be run on top of a paravirtualized VMM. However, even in cases where the operating system cannot be modified, components may be available which confer many of the significant performance advantages of paravirtualization; for example, the XenWindowsGplPv project provides a kit of paravirtualization-aware device drivers, licensed under GPL, that are intended to be installed into a Microsoft Windows virtual-guest running on the Xen hypervisor.

Paravirtualization With Xen On CentOS

Paravirtualization With Xen On CentOS 5.4 (x86_64) | HowtoForge – Linux Howtos and Tutorials.

This tutorial provides step-by-step instructions on how to install Xen (version 3.0.3) on a CentOS 5.4 (x86_64) system.

Xen lets you create guest operating systems (*nix operating systems like Linux and FreeBSD), so called “virtual machines” or domUs, under a host operating system (dom0). Using Xen you can separate your applications into different virtual machines that are totally independent from each other (e.g. a virtual machine for a mail server, a virtual machine for a high-traffic web site, another virtual machine that serves your customers’ web sites, a virtual machine for DNS, etc.), but still use the same hardware. This saves money, and what is even more important, it’s more secure. If the virtual machine of your DNS server gets hacked, it has no effect on your other virtual machines. Plus, you can move virtual machines from one Xen server to the next one.

I will use CentOS 5.4 (x86_64) for both the host OS (dom0) and the guest OS (domU).

This howto is meant as a practical guide; it does not cover the theoretical backgrounds. They are treated in a lot of other documents in the web.

This document comes without warranty of any kind! I want to say that this is not the only way of setting up such a system. There are many ways of achieving this goal but this is the way I take. I do not issue any guarantee that this will work for you!

The Coolest Server Names – Server Fault

The Coolest Server Names – Server Fault.

The funniest server name story I have is from when I worked at the Kennedy Space Center. On our particular project, our main server was named snowwhite, and the 7 client workstations were named after the Seven Dwarves. The kicker is, one day one of our engineers ran into a Disney Imagineer who worked at Walt Disney World, and they started talking about server names. The Disney Imagineer said “that’s funny, we have a group of servers named columbia, challenger, atlantis, and discovery.”



  • There’s a TONNE of them.
  • You’ll never run out of names.
  • They’re easy to Type:
  • Volcanoes are used for volatile servers
  • Long mountain names like KILIMANJARO are servers that you don’t want people to log onto
  • Different Mountain RAnges can serve as Clusters or a SAN. (The Rockies, Andes, Alps)
  • It’s always the user’s fault when they crash into a mountain
    • Mountains don’t crash
  • However, sometimes they explode (VESUVIUS)
  • You can rank them by Height and represent many of them pictorially in Network diagrams. (The Matterhorn, Mt. Fuji)
  • Mountains are great Security fortresses (Why do you think China wants to keep Tibet… it’s a plateau beside India!)
  • They are visible from outer space.
  • They can be classified in many different ways.
  • They can be Local (Intranet Servers) or in other countries/continents (WANs)
  • They are common to ALL people in all countries.
  • They can be named after people’s local hometown mountains. (When I was a kid I climbed to the peak of x mountain)