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/mic...200%2049359708

[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.

[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