I know this is a very noobie question, I apologize. I've used google and seen many different answers.


Do you need LVM's or not for Xen? I was under the impression you did, but after reading up on a few other places I guess you don't?


If you don't need LVM's would this be okay?

* /boot 200 MB (ext3)
* swap 32GB~48GB
* / 30GB (ext3)
* /vm the rest (ext3)



Then I would do....
yum install kernel-xen xen
vi /etc/grub.conf and select the correct kernel
*reboot*

Right? Please do not flame me, I am just trying to learn :)

Yep, CentOS 5.3 Xen install should be as simple as: yum install kernel-xen xen, and reboot into Xenified kernel. In general LVM storage is preferable for your VMs, but obviously you may have other specific requirements.

You only *need* LVM if you have a kernel that supports VT and plan on rolling out Windows based VEs.

Note that you can only do Windows virtualization w/ LVM + Processor w/ VT support.

Most workstation / desktop class machines hard-disable VT support, even if the installed chip technically supports it. Usually requires a server class box to get there.
You can, however, do *nix based VEs all day long with or without LVM / VT proc.

Your mounts look good, and yep, it's that easy to install.

If you don't need Windows, you can also try out OpenVZ if you haven't already.
It's worth a look, just to know the differences / similarities. I actually prefer OVZ for *nix based development clusters, but, that all depends on your needs, preferences, etc.

Hope that helps :)

You only *need* LVM if you have a kernel that supports VT and plan on rolling out Windows based VEs.

Note that you can only do Windows virtualization w/ LVM + Processor w/ VT support.

Most workstation / desktop class machines hard-disable VT support, even if the installed chip technically supports it. Usually requires a server class box to get there.
You can, however, do *nix based VEs all day long with or without LVM / VT proc.

Your mounts look good, and yep, it's that easy to install.

If you don't need Windows, you can also try out OpenVZ if you haven't already.
It's worth a look, just to know the differences / similarities. I actually prefer OVZ for *nix based development clusters, but, that all depends on your needs, preferences, etc.

Hope that helps :)

We already utilize Virtuozzo, and we could save a lot of money in the long run w/ Xen.

I don't have an interest in Windows.

I hear ya on the licenses...I primarily use OpenVZ and Xen, both w/wo LVM/VT as a development environment for our 25 programmers. Our only license saving grace is our MSDN subscriptions, which allow us to run them in dev environments, although the subscription is still freekin' higher than my ex-wife's alimony.
For Dev, I'm moving from VMWare (ESX) to these platforms for much the same reason. You sure can't beat the price, and I can re-claim some SAN space. :)

File based storage DomU's will have slower disk access than if they were LVM.

Your also more likely to incur disk corruption.

Definitely use LVM.

File based storage DomU's will have slower disk access than if they were LVM.

Your also more likely to incur disk corruption.

Definitely use LVM.

I see my response was taken. ; ). bump

I would recommend LVM also. We installed Xen and used the tap:aio image storage method and it was way too slow.

DO NOT USE FLAT FILE WITH XEN. Disaster.

DO NOT.

Filesystem corruption :eek:

Definitely use LVM.

+1
Doesn't make big differences after all when setting up. Definitely use LVM for production use.

You only *need* LVM if you have a kernel that supports VT and plan on rolling out Windows based VEs.

That is a VERY silly and wrong answer. You can actually run Windows on a loopback (eg: an HDD image on a file), the issue is the same as for other VMs: speed mainly. Both HVM and pv_ops VM will run on file or LVM back end, and in fact, Xen doesn't care what type of device it will use, Xen just need a device, whatever it is, if ioctl calls are working, then it's fine... You can use ANY device.

Thomas

That is a VERY silly and wrong answer. You can actually run Windows on a loopback (eg: an HDD image on a file), the issue is the same as for other VMs: speed mainly. Both HVM and pv_ops VM will run on file or LVM back end, and in fact, Xen doesn't care what type of device it will use, Xen just need a device, whatever it is, if ioctl calls are working, then it's fine... You can use ANY device.

Thomas

According to the Xen requirements, and my experience, VT support / LVM is required to virtualize Windows (and actually create templates).

Would that be wrong?

I make a living out of being silly. I'll never stop that.

Explain to me exactly what prevents you from using a file loopback or any other device?

I do agree that VT (or it's AMD equivalent) is required, but LVM is not (even though I would strongly advise for it).

Thomas

Explain to me exactly what prevents you from using a file loopback or any other device?

I do agree that VT (or it's AMD equivalent) is required, but LVM is not (even though I would strongly advise for it).

Thomas

Explain to me exactly why you want to be so arrogant with me?

I'm just going by Xen's requirements and how I got it to work. I just use it for our companies dev environment so we can run win cheaply for testing scenarios and new app builds. I'm much more of an OpenVZ guy myself, I'm no Xen expert. I'm sure there are many ways' to get esoteric about most technologies, but at the end of the day, we're just trying to simply answer OPs question and and make it as easy as possible.

Finding a nice way to get a point across is probably out of the question, hum?
Or is that idea silly, too?

Why do you think I'm arrogant? Because I wrote that you were wrong? So, anyone saying you are wrong is arrogant?

Or is it the word "silly" that disturbed you? Relax man...

Anyway, I insist, using a file loopback for an HVM domU works, and is not at all something exotic (it's just the slow, and wrong, way to do things).

Thomas

That is a VERY silly and wrong answer.



?

Peace out.

Tsss... I said the answer was silly and wrong. I can say it again. I didn't say YOU were silly. Can't you make the difference?

Thomas

You Need VT to Run Windows DomU on Xen (and in every other case if you want to run Fully Virtualized DomU), but you can run it with file based storage (loop devices through tap:aio), doesn't have to be phy (LVM based). I confirmed that because I have tried it before.

Tsss... I said the answer was silly and wrong. I can say it again. I didn't say YOU were silly. Can't you make the difference?

Thomas

I know a holier-than-thou attitude when I hear one.

And that's all I have to say about that.

Focker...out....