I always have been a Vmware person, but I am wondering if I am missing anything. Anyone here used Xensource at your work? Can you make any good supporting arguments if Xen is better than Vmware?

Thanks

I didn't use xen, however I read some article mention if we want to run Windows in xen, we need to have new type of processor. Like Centrino duo or xeon. However, due to the hardwar resource is share by all client os, so xen have better performance.

Vmware, is kind of userfriendly tools. I like it very much. At this moment we can obtain both for free.

As far as I know Xen and VMware have totally different approach towards virtualization i.e. Xen uses paravirtualization whereas VMware uses native/full virtualization.
paravirtualization provides special layer ( I guess its called Hypervisor) to access the hardware directly, this results in better performance but requires modification in Guest OS.
In order to use unmodified Guest OS using paravirtualization technique, the underlying hardware must support H/W level virtulization such as Intel-VT support.

On the other hand, native virtualization works by fully simulating the hardware this resulting in using Guest OS without any modifications but results in relatively lower performance.

You might also wanna look VirtualIron, a new product in virtualization which uses Xen and Qemu behind the scenes.

Hope it helps.

Ciao
hawk
------------------------------------------------
http://www.o3magazine.com
"The focus of o3 is on the use of Free and Open Source (FOSS) software in Enterprise and Business environments."

Would servers running Xen products gain a substantial speed boost by utilizing paravirtualization? I thought these chips are designed so you don’t have to paravirtualized. I thought the purpose of these enhanced VT chips was give you more access to the hardware. I thought paravirtualization was the software approached to VT chips. I am assuming these new chips are made so extra control of routing of device memory and irqs, so the hardwares can access them from the multiple channels. I haven’t read it about it yet. I briefly overheard it through a podcast. I am way too busy to keep up with all product trends. These new enhanced features seem nice, but I wonder how far we are to full 3D support through VM. It will be ideal for Desktop migrations. So, how are the features in Xen? Does it have more controls and virtual device options? How does it share process load among other VMs? Does it seem better than Vmware? I wish there is a way certain VM machine can’t dominate all the process loads like prevent testing VM from dominating production VM. Like assign 25% of the resources (cpu, memory, load, etc) to testing and 75% to production.

Anyway, I did't use Xen (I study it before during initial release, however I failed to install it). I'm happy with vmware because of I have 1 centrino single core processor, not able to run Windows in Xen.

Regards,
Ks

I would suggest if you are not flavour centric and are looking for a linux server virtualisation option, then my choice is OpenVZ, hands down. It has true native performance, unlike VMWare which has NEAR native perfomance.

A fairly good comparsion of virtual options is at http://en.wikipedia.org/wiki/Compari...rtual_machines

OpenVZ on CentOS is a doddle. VMWare I find quie cumbersome, whereas Xen lost me at their Windows licensing version and the fact that it requires HyperVisor support.

OpenVZ runs on a PIII server in a flash or a Dual Xeon Quad core just as well. It needs no latest and greatest and that is why it runs native.

OpenVZ is an absolute pleasure!!! Well done to the development team.

I stopped using RHEL many years ago, but I will give it a shot. It seems like based on searches on newsgroups, many people seem to enjoy it. Thanks for the info. I will install it on my home server before I do some damages at the client site.

Well then here is a quick howto build a CentOS OpenVZ server and two Virtual Environments (VEs), just I case it helps you. OF COURSE this has the IPs I used, they should be replaced with whatever IPs you use (this is not necessarily for your benefit netlogic, more for the random person that may stumble upon this and try it )

#### OpenVZ server build ####

# Install minimal CentOS with disabled SELinux

yum -y update
cd /etc/yum.repos.d
wget http://download.openvz.org/openvz.repo
rpm --import http://download.openvz.org/RPM-GPG-Key-OpenVZ
yum install ovzkernel-smp
### OR (I found that yum worked on one system but had to use rpm on another)
rpm -ihv ovzkernel-2.6.18-8.1.8.el5.028stab039.1.i686.rpm

# /etc/sysctl.conf file. Here is the relevant part of the file;
#please edit it accordingly. Only lines with two comments are
#commented out lines with one comment are essentially uncommented lines.

vi /etc/sysctl.conf
## On Hardware Node we generally need
## packet forwarding enabled and proxy arp disabled
net.ipv4.ip_forward = 1
net.ipv4.conf.default.proxy_arp = 0
## Enables source route verification
net.ipv4.conf.all.rp_filter = 1
## Enables the magic-sysrq key
kernel.sysrq = 1
## TCP Explict Congestion Notification
##net.ipv4.tcp_ecn = 0
## we do not want all our interfaces to send redirects
net.ipv4.conf.default.send_redirects = 1
net.ipv4.conf.all.send_redirects = 0

#SELinux should be disabled. To that effect, put the following line
#to /etc/sysconfig/selinux: SELINUX=disabled

shutdown -r -t 1 now

yum -y install vzctl vzquota
/sbin/service vz start
yum -y install vzpkg vzyum vzrpm43-python vzrpm44-python
yum search vztmpl
yum -y install vztmpl-centos-4.i386
vzpkgcache centos-4-i386-minimal
rpm -Uvh http://download.openvz.org/contrib/u...0-2.noarch.rpm
rpm -Uvh ftp://ftp.pbone.net/mirror/ftp.sourc...0-1.noarch.rpm

# To create and start a VE, run the following commands:
# vzctl create VEID --ostemplate osname
# vzctl set VEID --ipadd a.b.c.d --save
# vzctl start VEID
#Here VEID is the numeric ID for the VE; osname is the name of the OS template for the VE, and a.b.c.d is the IP address to be assigned to the VE.
#Example:
vzctl create 1921682188 --ostemplate centos-4-i386-minimal
vzctl set 1921682188 --ipadd 192.168.2.188 --save
vzctl start 1921682188

#Your freshly-created VE should be up and running now; you can see its processes:
vzctl exec 1921682188 ps ax

#To enter VE give the following command:
vzctl enter 1921682188

#To exit from VE, just type exit and press enter:
exit

#To stop the VE:
vzctl stop 1921682188

#And to destroy VE:
vzctl destroy 1921682188

###### Cloning a VE

# OLDVE=1921682188 NEWVE=1921682189 # Just an example
vzctl stop 1921682188
mkdir /vz/root/1921682189
cp /etc/vz/conf/1921682189.conf /etc/vz/conf/1921682189.conf
mkdir /vz/private/1921682189
pushd /vz/private/1921682188; tar c --numeric-owner * | tar x --numeric-owner -C /vz/private/1921682189; popd
vi /etc/vz/conf/1921682189.conf
# Change the IP_ADDRESS
vzctl start 1921682189
vzctl start 1921682188

#Because the base VE is a minimal CentOS system it is handy to have yum, below is a script that installs all of yum's dependancies and yum.
#Please note that the version numbers below may need updating!!!

####################
##
## Misc and YUM installs
##
####################

#correct your GATEWAY, as it will probably NOT be the default!!!
mv /etc/sysconfig/network /etc/sysconfig/network.original
touch /etc/sysconfig/network
echo "NETWORKING="yes"" >> /etc/sysconfig/network
echo "GATEWAY="xx.xx.xx.xX"" >> /etc/sysconfig/network
#Where xx.xx.xx.xx is the IP of your gateway
# Add nameserver
touch /etc/resolv.conf
echo "nameserver xx.xx.xx.xx" >> /etc/resolv.conf
#Where xx.xx.xx.xx is the IP of your nameserver, do it twice if there are two nameservers
service network restart

rpm -Uvh http://mirror.centos.org/centos-4/4/...1.4-3.i386.rpm
rpm -Uvh http://mirror.centos.org/centos-4/4/....3-13.i386.rpm
rpm -Uvh http://mirror.centos.org/centos-4/4/...-14.4.i386.rpm
rpm -Uvh http://mirror.centos.org/centos-4/4/...16-10.i386.rpm
rpm -Uvh http://mirror.centos.org/centos-4/4/...16-10.i386.rpm
rpm -Uvh http://mirror.centos.org/centos-4/4/...5.7-4.i386.rpm
rpm -Uvh http://mirror.centos.org/centos-4/4/...entos.i386.rpm
rpm -Uvh http://mirror.centos.org/centos-4/4/...3.6-2.i386.rpm
rpm -Uvh http://mirror.centos.org/centos-4/4/...1.2.1.i386.rpm
rpm -Uvh http://mirror.centos.org/centos-4/4/...7.1-4.i386.rpm
rpm -Uvh http://mirror.centos.org/centos-4/4/...onptl.i386.rpm
rpm -Uvh http://mirror.centos.org/centos-4/4/...8-2.noarch.rpm
rpm -Uvh http://mirror.centos.org/centos-4/4/...tos.noarch.rpm
yum -y update
yum -y install wget
rpm -Uvh http://download.openvz.org/contrib/u...0-2.noarch.rpm


Have fun, go surfing

I installed both Xen and VMware. Xen on my desktop PC, VMware on the Notebook. Why?
Well, first of all only the desktop PC has and AMD processor with the virtualization extentions - the notebook has only a PentiumM.
Second, I run servers (incl. Windows) on he desktop and in such a case you get best performance using Xen.
Third, I do a little bit of multimedia on the notebook and as Xen does not support yet audio nor accellerated 2 or 3D graphics (not sure about USB connections and other stuff), only VMware comes into the picture.

Just a small note. The latest versions of VMware Workstation support some sort of paravirtualization.

From the docs:

"If you have a VMware VMI (Virtual Machine Interface) enabled kernel in the guest operating system, you might see improved performance if you enable paravirtual support in the virtual machine."

We use Xen in our development environments for ease of support but it's never proved stable enough to use in our production environment. There we use plain VMware server.

Which version of VMWare are you talking about?
My experience has been that VMWare running on bare iron beats anything out there; hands down. The free version has provided good; performance on Ubuntu 6.06. The free version is running 1 WinNT Back Office server, 2 FreeBSD 5.5 servers (one for OpenVPN the other for Samba)and 1 NT workstation for NetOP. The hardware is an IBM x Series 336 with 2 gig of ram. Our uptime has been over a year with no performance issues and with over 40 users on the Samba server and 5 to 10 on the others.
Our experience with the GSX version is even better. We were able to consolidate 1 Oracle and 3 MySQL servers into one.
Unfortunately, my RedHat experience was early in the game for them and compared to VMWare not really a match.

We use VMWare on RHEL5 despite it having Xen available. Xen just doesn't compare to VMWare for our needs, and paravirtualization is slower than full virtualization.

Xen's configuration utilities are nowhere near as rich as VMWare's.

If you're going to spend money, get VMWare ESX, if you want free go with VMWare Server.

At this point in time I have yet to see any reason to mess with Xen, all our trials with it provided no extra functionality over VMWare and a introduced a lot more hassle.

Interestingly I have OpenSuSE 10.2 Xen running on AMD Opteron box and find paravirtualisation much faster than full virtualisation - very close to host performance for networking and disk. Limited set of management tools as yet compared with VMWare and may not be stable enough for production use - depends on what you want it for - I'm using it in a test environment currently.

Hi all,

I agree with all you of that both Xen and VMware has his advantages and disadvantages. I have came across a good comparison which show most of these and I hope it will help.

ITComparison.com VMware Infrastructure 3 VS Citrix Xen Enterprise.