gmane.comp.emulators.xen.user

I can run any livecd as domU, using ParavirtOp

Flako — 2012-05-16T22:33:55

Hello
Do not know if I'm mistaken, or I need to look more on the Internet.
I run a rescue cdlive, especially SystemRescueCd.
From what I understand now all have kernel support in dom0 and domU
ParavirtOps therefore concluded that it should be able to run
SystemRescueCd (kernel 3.0.13)

This is so? I can run SystemRescueCd, modifying one parameter of
isolinux SystemRescueCd?

Thanks for being up here. (I too am sorry my English)

Re: Xen or KVM

Waldirio M Pinheiro — 2012-05-16T21:57:55

Hello friends

In my opinion the diference is, this environment is test/desenv??  Ok ..., is homolog or production ??!! Hummm,  the client really need a help/support of one company! If The Client have a company who give The Support in OS and Products, ok but if isn't I recommend RedHat!

Now talking in RedHat we can talk about kvm and xen! There is a New product named RHEV, Enterprise Virtualization which will provide solutions to virtualization in HA with web manager, a cool suit confronting with vmware!

Ps: RHEV use kvm! ;-)

So I recommend a research about RHEV and Xen (RedHat recommendations)

Cheers
______________
Atenciosamente
Waldirio
msn: waldirio< at >gmail.com
Skype: waldirio
Site: www.waldirio.com.br
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LinkedIn: http://br.linkedin.com/pub/waldirio-pinheiro/22/b21/646
PGP: www.waldirio.com.br/public.html

"Nothing in life is to be feared. It is only to be understood."
--Marie Curie

Em 16/05/2012, às 16:54, Andrew Wells <agwells0714< at >gmail.com> escreveu:


____________________

Re: Xen or KVM

Andrew Wells — 2012-05-16T19:54:45

Is it just for servers, then go xen, do you plan on doing VDI (windows)
then again xen has good solutions.

Plan on doing Linux VDI look at Ovirt a kvm solution

On Wed, May 16, 2012 at 2:30 PM, Andrew McGlashan <
andrew.mcglashan< at >affinityvision.com.au> wrote:

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Re: Xen or KVM

Andrew McGlashan — 2012-05-16T18:30:28

Hi,

On 17/05/2012 4:04 AM, Itamar Reis Peixoto wrote:

Well, I've been using Xen, however there is a machine that would be
really good to use -- but xen will not work on it, fails to boot
properly.  IBM X3850 8864 .... so that machine now has Oracle Linux 6 on
it and I'll probably end up switching to KVM as it has much better
support in the kernel and I've had no help on the X3850 when I've asked
questions here.

Cheers

Re: "Boot loader didn't return any data!" -- Sisu

Sisu Xi — 2012-05-16T18:14:43

Hi, Chirs:

Thanks for your reply.

I reinstalled the system using CentOS. It's giving me same error
initially. However, when I remove all the *virt*, *qemu* packages, it
seems works fine now.

I don't know the reason for that.

Thanks.

Sisu

On Tue, May 15, 2012 at 6:25 PM, Chris Dickson <chrisd1100< at >gmail.com> wrote:

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Re: Xen or KVM

Itamar Reis Peixoto — 2012-05-16T18:04:43

if you ask in xen mailing list then the answer is xen
if you ask in kvm mailing list then the answer is kvm

both are good, try and make your choice.

Re: Xen or KVM

Niels Dettenbach (Syndicat IT&Internet — 2012-05-16T15:32:19

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Michael Egglestone <mike< at >estone.ca> schrieb:



...ouch,
sorry for my noise - i've misunderstanded your question completely.

There are many points why i would hardly prefer XEN over kvm or others in most cases when i want to virtualize Linux or NetBSD, but the most important are:

1.) XEN PV offers very ressource efficient hardware usage and a maximum of performance by a very low (to theoretically none in special circumstances) virtualization overhead.

2.) The security structures are the most transparent for me.

As i wrote: I mainly paravirtualize Linux or xen guests in server or appliance applications and even partly on desktops.

Desktop full virtualization might be more comfortable with solutions like VirtualBox or Parallels - but even this depends from what you would do and how far the user has to be invloved on which knowledge level into the VM management / usage as there is no such full (free) GUI for xen desktop virtualization afaik.


hth
best reg

Re: Best way to differentiate between virtual servers and non-virtual servers

jinho hwang — 2012-05-16T15:10:08


Sorry for the top-posting.

simon hobson wrote:
If the hypervisor is installed, and there's a /proc/xen directory with
stuff in it, and Xen commands (eg "xm list") do stuff - then you'll know
that this is a host system running under Xen.

If there's no Xen stuff installed, and no /proc/xen directory - then you're
likely running on bare metal.

I agree with Xen that I can have information from /proc/xen for both
virtual machine and domain0.

simon hobson wrote:
However, you really should not be having to do this. You should **KNOW**
without having to go looking around on a machine what it is. If you are
working on machines, and your management systems (even just a basic list of
what you have or are responsible for) does not give you this information
then you need to address that.

Traditionally people would keep "some sort of list" which would say "what
is it", "where is it", and "what's the admin/root password". These days
that should also include "is it a virtual host or client" - and have an
easy way to

Re: Xen or KVM

Michael Egglestone — 2012-05-16T14:47:30

#The question is why you personally like Xen? What benefits you getting over KVM?

I'm fairly new to Xen and virtualization for that matter, but I tested both
xen and kvm before I deployed my first live VM.
I ended up with xen simply for the fact that I liked the management
of the VM's better than kvm.
The .cfg files are easier to read and configure, and the xm tools are simple
and give quick, easy to read info.
We run a mix of Microsoft Server and Debian VM's. Xen hosted on Debian.
The online documentation and this user list were also important factors.

There was some discussion a few years ago about xen not entirely being in
the linux kernel and that bothered some folks, where kvm was built in.
But IIRC, I believe now that xen is part of the 3.x kernel.

Cheers,
Mike





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Re: Best way to differentiate between virtual servers and non-virtual servers

Simon Hobson — 2012-05-16T14:43:51

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

jinho hwang wrote:


Right, so after all that, you are talking about how you - as the 
administrator of a machine - determine if it's bare metal (non 
virtualised) system, or a virtualised system, or is a host for 
virtualised machines.

I don't know about other virtualisation technologies, but with Xen 
you just need to look at what's installed.

If the hypervisor is installed, and there's a /proc/xen directory 
with stuff in it, and Xen commands (eg "xm list") do stuff - then 
you'll know that this is a host system running under Xen.

If there's no Xen stuff installed, and no /proc/xen directory - then 
you're likely running on bare metal.


However, you really should not be having to do this. You should 
**KNOW** without having to go looking around on a machine what it is. 
If you are working on machines, and your management systems (e

Re: Best way to differentiate between virtual servers and non-virtual servers

jinho hwang — 2012-05-16T14:39:35

Hi Tait,

Thanks for your reply.

Let's say my project is an automated management with client-server setting,
and it can control cloud or non-cloud machines. One small software
installed in a client side can receive a command from the server, and it
executes the command and replies the results to the server. It might give a
company a good management tool to control the large system.

I am thinking there are no solid sole method for this problem. It might
help to overlap a couple of conditions to check. Like you said, MAC can be
one method to check, but it is hard to be sure whether the MAC address is
virtual machine's MAC or physical machine's MAC. I need to make sure which
one.

Jinho

On Wed, May 16, 2012 at 10:19 AM, Tait Clarridge <tait< at >taiter.com> wrote:

Re: Best way to differentiate between virtual servers and non-virtual servers

Tait Clarridge — 2012-05-16T14:19:04

Although I think that your idea is quite confusing, you could always
check out MAC addresses (unless someone is not using the standard or
default ranges) that may help you differentiate between
physical/virtual.

In terms of your project, you might want to consider that if you have a
person who is logging into a server and performing upgrades/reboots and
has no idea that it could be running multiple virtual machines... that
person shouldn't be logging into that server to begin with.

Tait

Re: Best way to differentiate between virtual servers and non-virtual servers

jinho hwang — 2012-05-16T13:58:25

Hi Simon,

Thanks for your reply.

Yes, if I have a control of computers, then I might be able to figure out
what is virtualized or not. Maybe, it might not necessary to know about it
if I am a user of machines. However, think that if I want to control all
the machines, either cloud or non-cloud setting, users are using.
Sometimes, the machine should have a problem or need upgrades, and I may
have to reboot the computer  to resolve the problem or upgrades. But if the
computer is a cloud hosting machine which has lots of virtual machines
running on the top of that. If I reboot that machine, it might cause a big
trouble because it will reboot all the virtual machines running on it.
Instead, I may have to live migrate all the virtual machines to another
physical machine, then I can reboot the system.

As the perspective of the infrastructure manager, not a user, knowing a
machine is a virtual machine or a physical machine helps how to manage the
machine.

I hope you understand what I am trying to do.

Jinho

On

Re: Best way to differentiate between virtual servers and non-virtual servers

Simon Hobson — 2012-05-16T13:00:41


I'm sorry, but I really really have no idea what you are trying to achieve.

For machines under my control (ie those I set up or administer) then 
I know if they are real or virtual - it's rather obviously a 
different process to setup a machine on bare metal compared with 
setting one up as a virtual machine.

For machines I'm not responsible for, then it's not my business and I 
probably have no need to know !


So, just what is it that you want to know about ? What is "my 
machine" ? Why do you need to know ?


To give some examples ...

a) You are renting "web hosting" somewhere.
You are only renting the web hosting, as long as it works to an 
acceptable level of performance then you have no need to know. There 
should be nothing related to it being real/virtualised which in any 
way affects your ability to host your site.

b) You use a shared computer in the office.
Again, as long as it provides the facilities/runs the applications 
your employer needs your to use then it makes no difference to you 
w

Re: Xen or KVM

Mark Schneider — 2012-05-16T12:36:00

Am 16.05.2012 12:04, schrieb Arindam Choudhury:

Arindam,

After playing for over a year with Xen (Xen/XCP/XenServer) and KVM I 
tend now to use KVM due to low I/O performance of Xen/XCP/XenServer when 
using HVM. PVMs in Xen have probably a bit better I/O-performance but 
quite a lot of overhead to manage it with different operating systems (I 
don't run any MS OS).

Due to my tests (HVM) on the same hardware (like HP DL385g7 servers with 
two Opteron 6180SE CPUs and 32 or 64GB RAM, an additional 
RAID-controller P410 (in total 16 hard disk drives) and additional quad 
port 1GBit NIC) the network performance on KVM is at least 3 times 
higher compare to Xen. Also the I/O-performance for storage (RAID60 or 
RAID50) is at least two times higher on KVM.

The free available version of XCP or XenServer has outdated templates 
for HVM / PVMs and it looks like that Citrix doesn't really have 
commercial interesst to improve them. I don't think that it will change 
in the near future as most active Xen developers a

Re: Allocating memory and cpu to Domain-0

Lloyd Dizon — 2012-05-16T12:15:48

I found some information that explains this a bit. But still doesn't make sense:

http://www.novell.com/support/kb/doc.php?id=3559698

Basically the article above says that:

the total system memory minus the amount of memory assigned to dom0
equals the amount required by the hypervisor

TotalMem - Dom0Mem =  memory for Hypervisor.

but Hypervisor /= Dom0.


So the question still remains, how do you calculate memory for Dom-0 ?


Other than that several interesting things recommended by the article:
"Lock down" the amount of memory assigned to dom0.
Disable ballooning
Do not restrict dom0 to a single VCPU
Only use Logical Volume Manager (LVM) on Dom0 or DomU, but not both

Re: Best way to differentiate between virtual servers and non-virtual servers

jinho hwang — 2012-05-16T12:03:33

Hi Simon,

Thanks for you reply. I understand your saying about 2). I think under
current situations (with many different hypervisors and their settings) it
might be hard to detect whether the machine is virtual or not with only one
method. That's why I listed many possible ways to detect it. If you can
share your idea how to detect the virtual machine, it might help many
people who try to know the current states of the machine.

I always wanted to know whether my machine is virtualized or not. Also, my
current project wanted me to find a way to do it.

Please, share your idea if you have any.

Thanks,

Jinho

On Tue, May 15, 2012 at 11:36 AM, Simon Hobson <linux< at >thehobsons.co.uk>wrote:

Re: Xen or KVM

2012-05-16T11:50:44

What type of guest OS do you plan to run?  Will it be Windows, Linux, or a
mix of the two?  If it is purely Linux, you may want to look at OpenVZ as
well as Xen and KVM since you mentioned the jobs would be I/O intense.  

 

-----Original Message-----
From: xen-users-bounces< at >lists.xen.org
[mailto:xen-users-bounces< at >lists.xen.org] On Behalf Of Arindam Choudhury
Sent: Wednesday, May 16, 2012 5:02 AM
To: xen
Subject: Re: [Xen-users] Xen or KVM

 

 

choosing

yes, My question should be if I want to run I/O intensive jobs. Which is
more suitable?

And also, to learn Xen 4, which materials you experts suggest?

Regards,

Arindam

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Re: Xen or KVM

2012-05-16T11:48:13

When you ask a bunch of Xen experts if they prefer Xen or KVM, you should be
able to guess the answer you will receive.  :-)

 

 

 

-----Original Message-----
From: xen-users-bounces< at >lists.xen.org
[mailto:xen-users-bounces< at >lists.xen.org] On Behalf Of Arindam Choudhury
Sent: Wednesday, May 16, 2012 4:50 AM
To: xen
Subject: [Xen-users] Xen or KVM

 

Hi,

I am new to virtualization and I am having the obvious hassle of choosing
between Xen and KVM.

Can Xen experts help me with this?

Regards,

Arindam

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libxl vs pygrub in 4.1.2 on rebooting domU

Dmitry Morozhnikov — 2012-05-16T11:29:30

Hello, all.

There is a bug in 4.1.2, at least in gentoo. The question is if it 
already fixed or not.

If someone issue reboot command from inside domU using pygrub 
bootloader, then libxl, or more precisely, make_bootloader_args() in 
libxl_bootloader.c will append parameters --kernel, --ramdisk and --args 
on the second start. So, command line for the pygrub will look like:

usr/bin/pygrub --kernel=/var/run/libxl/boot_kernel.KyI4aX 
--ramdisk=/var/run/libxl/boot_ramdisk.th_SXc 
--args=root=UUID=15c4dce6-e5fe-493f-b738-32b8e7ef829e ro console=hvc0 
quiet  --output=/var/run/libxl/bl.nVj8nF/fifo --output-format=simple0 
--output-directory=/var/run/libxl/ /var/xen/vs92.img

But that is completely wrong from the pygrub side! It bail out with:

Traceback (most recent call last):
   File "/usr/bin/pygrub", line 783, in <module>
     data = fs.open_file(chosencfg["kernel"]).read()
IOError: [Errno 2] No such file or directory

Because there is no /var/run/libxl/boot_kernel.KyI4aX in inside of domU 
disk image.

So

Re: Xen or KVM

Fajar A. Nugraha — 2012-05-16T10:11:24

Just to be clear, by "the same result" here I mean the performance of
the three setup is roughly the same, the difference is not
statistically significant.