More virtualisation questions :)

[techyphil]

I'm wanting to go down the VMWare route to virtualise our current servers onto some meaty new ones.

 

We are looking at 3 powerful servers but i'm not sure about the following...

 

Does VMWare ESX Server allow Tape Drives to be seen by windows and if so is there a compatibility list or is it pretty generic?

 

What VMWare software do you have? VMMotion etc?

 

How do you backup these vmdisks? Do you snapshot them and only backup the snapshot files and keep an original seperate or something?

 

Have you experiences any issues with it. Things you have'nt been able to do that you can with a physical box. I get the idea that you've got faster recovery and you can go snapshot instantly. But having 2-4 OS's on one box also means you've got all your eggs in one basket. :S

 

Just need an idea how you run your virtual infrastructure really...

 

 

 

Thanks for any advice

[ChrisH]

If your going down the route of putting important servers onto VMware you will need hardware and software failover. This will mean another server ready to take over from a failing server and using Vmotion which will mean ££££ license costs. You will also need some centralised storage as well like a SAN.

[DMcCoy]

If your going down the route of putting important servers onto VMware you will need hardware and software failover. This will mean another server ready to take over from a failing server and using Vmotion which will mean ££££ license costs. You will also need some centralised storage as well like a SAN.

 

You don't *have* to use high availability, although you will probably want vmotion which is not part of standard, I still have standard + vmotion as a legacy from 2.5 licensing.

 

Nor do you need a spare server for example, just sufficient capacity to spread the load to those that remain.

[DMcCoy]

I'm wanting to go down the VMWare route to virtualise our current servers onto some meaty new ones.

 

We are looking at 3 powerful servers but i'm not sure about the following...

 

Does VMWare ESX Server allow Tape Drives to be seen by windows and if so is there a compatibility list or is it pretty generic?

 

What VMWare software do you have? VMMotion etc?

 

How do you backup these vmdisks? Do you snapshot them and only backup the snapshot files and keep an original seperate or something?

 

Have you experiences any issues with it. Things you have'nt been able to do that you can with a physical box. I get the idea that you've got faster recovery and you can go snapshot instantly. But having 2-4 OS's on one box also means you've got all your eggs in one basket. :S

 

Just need an idea how you run your virtual infrastructure really...

 

 

 

Thanks for any advice

 

Vmware ESX has some pretty strict compatability requirements, the supported hardware is listed on the site. I think scsi passthru may be supported but can be a headache to get working.

 

Using ESX standard + VMotion and VirtualCenter. Backing up with traditional OS agents for now, looking to export the images with backup exec 12.5 in the future (if I can get it any cheaper). Occasionally export the disk images to nas.

 

Snapshots are useful, but you don't want to leave one open continuously for example as it will create a massive redo log and effect performance.

 

 

http://kb.vmware.com/selfservice/microsites/search.do?cmd=displayKC&docType=kc&externalId=1000024&sliceId=2&docTypeID=DT_KB_1_1&dialogID=49361663&stateId=0%200%2049359708

Edited November 17, 2008 by DMcCoy

[techyphil]

Yeh i'm not looking for mass failover hardware. Have 40% load ideally on each server averaged out and then move VM's across should we need to take one offline.

 

What spec SAN's are you using and is it using FC or iSCSI or something else?

[zag]

Just out of interest why would anyone want to virtulize important servers? Doesn't that increase the likelihood of you loosing a significant part of your network if the hardware fails?

 

Personally I would much prefer multiple servers so if one died I could get it back and running pretty quickly.

 

Maybe I'm missing something?

[dhicks]

Just out of interest why would anyone want to virtulize important servers?

 

To decrease the likelihood of you loosing a significant part of your network if the hardware fails. If the hardware running a VM conks out you simply start up a copy of that VM on a different physical server. We have our servers set up to mirror VMs between separate physical machines in real time, so should one server explode another can take over in seconds (ish) with no loss of data (ish).

 

--

David Hicks

[Ric_]

To decrease the likelihood of you loosing a significant part of your network if the hardware fails. If the hardware running a VM conks out you simply start up a copy of that VM on a different physical server. We have our servers set up to mirror VMs between separate physical machines in real time, so should one server explode another can take over in seconds (ish) with no loss of data (ish).

 

As you say, HA (High Availability) and DR (Disaster Recovery) are the major reasons for virtualisation. With the correct infrastructure, your only downtime would be the time taken to restart a VM on a new bit of tin - this can be done automagically too!

 

You'll see my posts dotted about... I chose Citrix XenServer because it saved me large wads of cash over VMWare. XenServer 5.0 features HA, XenMotion (live moving of VMs between hosts) and all manner of goodies - plus less licensing restrictions than VMWare!

 

Only 'problem' with XenServer is that you can't expose a LUN (e.g. volume on a SAN or tape drive) to a VM but it isn't a disaster. With something like Sun's openstorage solution you can attach your tape library to your storage solution.

[DMcCoy]

Hardware independence, snapshots (so you can patch and revert if it fails for example). Templates for deploying new servers in a few minutes.

 

I can upgrade my blades and the ESX OS without any end user disruption by migrating the machines as needed.

 

Not that this is not without issues (Windows licensing for example, although MS applications have had their rules relaxed slightly).

[wesleyw]

Ric being completely new to virtualisation what do you mean by expose a vm to a volume? you mean they can't be directly connected to one or something else?

[Theblacksheep]

vmotion seems to have moved into the 'enterprise' V3 pricing band.

 

Anyone use VDI? As the bundle seems worth getting if you are thinking of getting V3 standard.

Edited November 18, 2008 by Theblacksheep

[Ric_]

Ric being completely new to virtualisation what do you mean by expose a vm to a volume? you mean they can't be directly connected to one or something else?

 

The way SANs work, you tell the SAN to make a LUN (bit of disk space) available to a server and it sees that like it's a local device.

 

XenServer (currently) does not allow LUNs to appear directly to VMs, instead you need to expose the LUN to the hsot and create virtual disks.

 

It is for this same reason that you cannot expose a tape library to a VM.

[Ric_]

vmotion seems to have moved into the 'enterprise' esx pricing band.

 

Anyone use VDI? As the bundle seems worth getting if you are thinking of getting V3 standard.

 

VMotion was one of the features I wanted from virtualisation... hence why I chose XenServer (Enterprise has XenMotion) and saved over £3k!

[Theblacksheep]

VMotion was one of the features I wanted from virtualisation... hence why I chose XenServer (Enterprise has XenMotion) and saved over £3k!

 

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)?

 

thanks

[wesleyw]

You'd need TS cals for XenApp as its the new name for Presentation server.

 

Wes

[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.

 

--

David Hicks