More virtualisation questions :)

[wesleyw]

You can get virtual ready SANs I think? I think the SAN option is too expensive for us at the moment. So see if I'm getting this right. Instead of creating a LUN to the virtual server you create one to the host first then add it to the virtual server as you would normal hdd space?

[Ric_]

Do you also use Xen desktop and does this also require additional TS licencing? Or like VDI is it a standalone virtual desktop provider?

Can you log into a VM via the web? (provide VM desktops to home)?

Desktop Virtualisation is a related, but separate, technology. Check out the videos at Citrix Systems XenDesktop Demos - it looks REALLY cool.

Yes you can run XenDesktop over the web from what I can tell.

You can get virtual ready SANs I think? I think the SAN option is too expensive for us at the moment. So see if I'm getting this right. Instead of creating a LUN to the virtual server you create one to the host first then add it to the virtual server as you would normal hdd space?

Erm... all SANs are 'virtualisation ready' but some have features that make them 'better' than others - for instance NetApp has technology that works particularly well with XenServer (see Citrix Systems Citrix Alliances Strategic Partner NetApp ) but my EMC SAN does everything I need.

It is worth thinking about the fact that consolidation of, for instance, 4 servers onto 2 would mean that you would only need 4 local disks (although technically you don't even need these) rather than a minimum of 8. You have also saved yourself the cost of 2 physcial servers. All told, this could have been a hardware saving of £4k+ which would be sufficient to start looking at an entry-level SAN.

[sammy]

Hi Guys,

I agree with Ric the XenServer product is excellent and quite a bit cheaper then VMWARE which when you bundle the VMOTION and VirtualCentre management suite in to centrally manage really hikes the prices up.

However there are alternatives in the market, we have been working with a company called Virtual Iron selling virtualisation into coporates and education because it has almost identical features to VMWARE but at a third of the cost of VMWARE.

We are a Citrix Gold Partner, a HP Preferred 2009 Gold, VMWARE Registered etc and we sell all the technologies mentioned above, but ultimately when cost comes into the equation such as with education....so far Virtual Iron is really the only option.

I dont want to do the heavy sell here, because im also a technical guy myself and so its really for you guys to check it out. If any of you want to have a chat about it, feel free to contact me. Virtual Iron - True Server Virtualization for Everyone

Ps. Sorry about all that shiny gold talk above...i know its cheesy

[K.C.Leblanc]

Sorry to jump on someone else's thread. But it's a quicky. I'm already aware of Xen, VMWare, HyperV and Virtual Iron. Anything else I should be looking at?

[dhicks]

but ultimately when cost comes into the equation such as with education....so far Virtual Iron is really the only option.

You all do know that Xen is free, right?

--
David Hicks

[dhicks]

Sorry to jump on someone else's thread. But it's a quicky. I'm already aware of Xen, VMWare, HyperV and Virtual Iron. Anything else I should be looking at?

Wikipedia, of course. You should probably add KVM to your list above.

--
David Hicks

[tmcd35]

Just read through this thread and thought it may be worth pointing a couple of things out.

Yes Xen is free - but so is ESXi and VMWare Server. With both you pay for the big features (Xen is cheaper I believe). Personally biased towards VMware I think ESXi is a good option these days. Certainly starting to look at it here.

SAN's don't have to be expensive - but you do get what you pay for in terms of performance. See SANMelody for a very good, cheap, alternative to a regular SAN.

IMHO, vMotion and HA are over priced and probably under utilised in a school environment. If you are using a SAN or NAS as a common storage area for the VM's then it's a trivial process to restart the machines on another server.

[dhicks]

Yes Xen is free - but so is ESXi and VMWare Server.

Good point. I never see ready-made VM appliances for Xen, either.

With both you pay for the big features

Don't know what you count as a "big feature", but I've got real-time replication of Xen VMs between separate hardware for no extra cost (beyond that of the hardware, obviously).

--
David Hicks

[wesleyw]

How did you manage that?


Wes

[dhicks]

How did you manage that?

We simply use DRBD to mirror volumes. When data is written to one volume, DRBD copies it over the network to another. Having a dedicated network link is nice (and very cheap - just normal £10 gigabit network cards and cable is fine) but not absolutely necessary. DRBD's manual is very good, especially for an open source project. DRBD can mirror standard block devices and in turn presents its mirrored devices as standard block devices, so it can be slotted in in the "storage protocol stack" along with encryption and filesystem-based anti-virus if you like.

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David Hicks

[DMcCoy]

We simply use DRBD to mirror volumes. When data is written to one volume, DRBD copies it over the network to another. Having a dedicated network link is nice (and very cheap - just normal £10 gigabit network cards and cable is fine) but not absolutely necessary. DRBD's manual is very good, especially for an open source project. DRBD can mirror standard block devices and in turn presents its mirrored devices as standard block devices, so it can be slotted in in the "storage protocol stack" along with encryption and filesystem-based anti-virus if you like.

--
David Hicks

Although the issue with that is you have doubled your hardware and storage requirements, along with not having hot migration of the machine state itself. It's also not terribly efficient on a large scale.

It is a lot cheaper from a VM software point of view though.

[dhicks]

Although the issue with that is you have doubled your hardware and storage requirements

You've doubled your requirements for harddrives and decent RAID controllers, but you'd have needed machines to do processing anyway. You also have fully redundant hardware and local access speeds to storage.

along with not having hot migration of the machine state itself.

Xen supports live VM migration for free.

It's also not terribly efficient on a large scale.

I agree - at some point in scale (measured by cost of equipment), it's worth centralising/decoupling your storage. I don't know where that point is, but I'm guessing it's somewhere past where most schools would be interested in.

--
David Hicks

[DMcCoy]

You've doubled your requirements for harddrives and decent RAID controllers, but you'd have needed machines to do processing anyway. You also have fully redundant hardware and local access speeds to storage.



Xen supports live VM migration for free.



I agree - at some point in scale (measured by cost of equipment), it's worth centralising/decoupling your storage. I don't know where that point is, but I'm guessing it's somewhere past where most schools would be interested in.

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David Hicks

Does it work without a shared storage medium?

You also keep saying centeralised storage is not something most schools would be interested in, but there are a great many of us here who have already done so. It certainly wasn't common when I did ours some years ago, but it's worth looking at for any large school these days.

[wesleyw]

Xen supports live VM migration for free.

Xen Express doesn't only the paid for versions?

[webman]

Xen Express doesn't only the paid for versions?

I think dhicks means it is possible because he uses DRBD. Essentially he has a second set of servers whose disks are an exact replica of that of the primary set of servers; all running Xen and their respective virtual servers - stored on the 'local' server HDs.