What

The Official Xen User Group in Los Angeles has been announced on the Xen.org Web site.
It is to take place in a not-yet-disclosed location in Los Angeles, CA on July 30th, 2010.
Stay tuned to Xen.org Blog and TheBitsource.com to get updated when we reveal the location.

Who

Jeremy Fitzhardinge, Principal Engineer, Citrix, will be our guest and presenter.
This user group is brought to you for your virtualization enjoyment by Xen.org and TheBitsource.com

Click here to see the original announcement

Click here to register

About Jeremy Fitzhardinge

Jeremy attended the University of Technology, Sydney, where he was thoroughly distracted by Linux, which he has been contributing to since around 1993.  He did various things over the years (including fileserver filesystems, settop box graphics and Valgrind – the swiss army debugging tool) until he joined Xensource in 2006.  Since then he has been primarily working on improving Linux’s support for Xen, particularly getting all the Xen-related changes into mainstream Linux.  He lives in San Francisco with a wife, two kids and a grumpy cat.
Slides from Jeremy’s previous Xen Summit presentations:

http://www.xen.org/files/xensummit_fall07/05_JeremyFitzhardinge.pdf

http://www.xen.org/files/xensummit_oracle09/JeremyFitx.pdf

By Ryan Compton

I had the chance to speak with Stephen Spector of Xen.org about his work on this exciting virtualization project. We spoke about the basics of Xen, Xen development, and Xen in Antarctica, which is one of the goals for the Xen Around the World project.

What does Xen do?

Xen is a collaboration between industry giants, universities, and hobbyists to provide an open source (GPLv2) hypervisor for server virtualization. The hypervisor provides a layer between the guest and the hardware allowing for multiple operating systems to be run on the same server.

How does Xen differ from other hypervisor’s?

Xen is developed by a combination of corporations where each company builds their unique strength into the software. Intel optimizes hardware, Oracle virtualized databases and Citrix works with desktop virtualization. VMware, our major propitary competitor, develops all their software alone and thus relies on a smaller support base.

Why is it exciting to be working in virtualization now?

Only about 20% of servers are virtual right now and that number is growing rapidly. As high speed internet becomes more widely available cloud computing will only continue to grow at least as fast as it has in the past few years. Xen is already being used for Amazon’s EC2 and Citrix systems’s servers.

How can people become involved with the development of Xen?

First off, get to our friendly mailing lists and participate in the conversations. The Xen hypervisor  is a highly sophisticated construct that most hobbyists are not involved with, at this level changes must be approved by the hypervisor’s creator, Keir Fraiser. Most of the development that we see from individuals comes at the management space layer. We also have people that contribute by  simply answering questions on the message boards or explain how they use Xen.

I noticed you have a project “Xen Around the World“, where are some of the more interesting places you’ve found Xen?

The goal here is to get Xen in Antarctica. So far we’ve hit every other continent but we still can’t find a way to get there. There is one group using Xen in a fairly remote part of Africa but we can’t seem to find out exactly what they are doing there. There’s also a group of guys in Britain who run horse racing bets on an OS/2 network, they used Xen to keep their bets going while they updated their hardware.

Anything coming up?

We’ve got a conference in San Jose on April 28th and 29th. That’s a real good place to be if you want to get to know some of the fine details of the hypervisor’s memory mapping.

For more information Steve can be found traveling to any of the following locations.

Ryan Compton’s Homepage http://www.math.ucla.edu/~rcompton/

Coverage of a chat with Stephen Spector, Xen Community Manager, about Xen training the the Xen.org team delivered at LISA this year amongst other things. Covered in the article: Future developments with Xen and training delivered from the de-facto Virtualization technology. Read it on the LISA blog here: http://lisa.usenix.org/2008/11/11/lisa-insider-the-xenorg-team-on-xen-training/

As the cloud computing boom continues to reverberate through the technology ultraverse, it seems as if there is more and more mention of Xen as the virtualization platform for making large scale clouds possible. There are a variety of solutions on the market for managing Xen cluster’s and it seems as if cloud computing becomes more prevalent amongst large key technology players, Xen appears to be the common mortar upon which cloud infrastructures are being built. Could it be Xen will be the new de-facto cloud infrsatrcuture component. I can see why it makes sense for cloud computing:

Large open source community support
Large commercial enterprise contributors on the open source side
Easy to manage and deploy (Citrix, Rocks, Ganeti).

A few key players using Xen for their cloud computing:
IBM Blue Cloud
Amazon Elastic Compute Cloud
Flexiscale
Enomalism

In VMware ESX server 3.0, Virtual machine performance can severely degrade when deploying a large number of virtual machines to a single ESX server. To help resolve this issue, the virtual memory arguments inside of ESX can be adjusted.

Some of the key virtual memory arguments that can be tuned are the dirty_ratio and lower_zone_protection. VMWare includes support for legacy ISA buses that can sometimes cause out of memory kills (oom-kills). By protecting this lower zone the propensity for oom-kills to occur can be lowered significantly.
For information on adjusting Linux virtual memory parameters please refer to the following tutorial (Login required as a part of USENIX membership. if you are an IT pro, I highly recommend joining the USENIX association anyway as you will receive acces to this document as well as many more):
https://www.usenix.org/publications/login/2008-04/pdfs/sacks.pdf

However in VMWare Virtual Infrastrcture 3.5, tuning the virtual memory settings for Linux can have the opposite effect, and it is best to let VMWare’s vmemctl Kernel process to handle resource allocation. The best way to tune Virtual machine performance in ESX 3.5 is to use resource pools and by efficient capacity planning.

Performance gains can be achieved by tuning the Linux kernel on VMWare’s ESX 3.0 and better performance and stability can be squeezed out of an over-utilized server. The need to tune virtual memory settings when running Linux on ESX 3.0 increases exponentially when installing any sort of java-based application server on this platform.

For more information on Linux Virtual memory and VMWare performance tuning see http://www.redhat.com/magazine/001nov04/features/vm/ and http://www.vmware.com/pdf/vi_performance_tuning.pdf