Why virtualise

[dhicks]

I assume once you have virtualised your servers you keep backups of the images. Where do you store them?

Fire safe.

I also assume each image has it's own IP address - but does that cause a bottleneck on the network card on the machine?

You can assign a VM its own physical network card (or any other physical resource, like a disk or disk array).

What products would you all advise that I look into? I know of VMWare - so is that the best one?

We use Xen, running on CentOS 5.1 and using DRBD to mirror VMs around to provide real-time backup in case of hardware failure (see several previous posts on this subject!).

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David Hicks

[dhicks]

So far only our main DC has proved a little difficult to virtualise - needs rebuilding as a VM.

Seemingly you can get confusion if you have more than one DC running - running as a VM causes time/date issues if you stop/restore the VM at any point. Probably fine if you only have one DC running.

It was installed on a VM but the MS-SQL server doesn't seem to like being a VM so that is about to be moved to a physical server.

Before you do - does assigning MS-SQL its own physical disk or (for preference) RAID disk array sort the problem? Some databases try to optimise their disk usage in various ways, and might get confused if they're using a VM disk image instead of a real, physical disk.

--
David Hicks

[powdarrmonkey]

We have virtualised practically everything across three physical servers. File servers, application servers, print servers, ghost server, and more besides. So far only our main DC has proved a little difficult to virtualise - needs rebuilding as a VM. The only other 'failure' we've had on the virtualisation front is our MIS. It was installed on a VM but the MS-SQL server doesn't seem to like being a VM so that is about to be moved to a physical server.

Odd, we've virtualised two domain controllers and 3 SQL servers without any problems, straight onto Xen.

[tmcd35]

We have two or three DC's virtualised but the PDC won't go. VM Convertor crashes out after at about 97%! And Ghost didn't work either. One of the machines problems is the Partitioning is odd to say the least (not my work!).

Theres a 10mb primary boot partition, followed by a 30Gb Logical drive that is also the System drive, followed by a 7Gb primary partition that is the C: drive. Never seen anything like it before!

As for SQL, I can't see what is wrong! Neither the physical server or the VM are reporting heavy usage - indeed processor are practically idling. The VM has 4 cores (two of which are dedicated to that VM) and 4Gb ram. Both Bromcom and my NM blame the slowness of some pages to respond on the fact that the server is a VM. Bromcom think that their is an incompatibility between MS-SQL and VMWare ESX. So the machine is being copied its own Physical box this half term. Personally I don't think it will solve the slowness problem - I think the speed issue is somewhere else.

Before you do - does assigning MS-SQL its own physical disk or (for preference) RAID disk array sort the problem? Some databases try to optimise their disk usage in various ways, and might get confused if they're using a VM disk image instead of a real, physical disk.

Yeah, we thought of this. The VM was originally hosted on our SAN. It was always running from it's own dedicated LUN on the SAN. But we thought this might be the bottle neck so we bought two SAS drive and put them in the physical ESX box (RAID-1) running the MIS. noticed only a slight speed gain from doing this. Everyone still blames VMWare for the speed issues.

[tbeach]

I have one question about vmware i can't work out in my head.

How do the clients connect join the dc?
Where do you run DHCP on the VM or the host?
How do you setup the VM network cards, as bridged or nat?
How do you connect other VM's to connect to that server again bridged or nat?

Many Thanks

[tmcd35]

It may help to think of the Physical Host server as a big kick-ass core switch and then each of the VM's are your servers connected to that switch.

[tbeach]

So do i assign a ip address to the host. Then the VM is then bridged which will have its own IP address and it will be running DHCP - DNS - AD. Would this be the correct way of doing things?

[powdarrmonkey]

Yes. All the servers are assigned resources so that they look just like a whole machine to themselves. They behave exactly as they would in the real world in terms of connecting to other nodes. Think of it like amalgamating many kettles into one big water boiler.

[garethedmondson]

SO let's say I decide to virtualise my WSUS server. Am I better creating it from scratch (I can do that at home and transfer it to school), or trying to virtualise my current server (which I would have to do in work).

What product would you recommend?

GJE

[powdarrmonkey]

I only have experience in Xen, for which the process (if you don't want to start from scratch, which would be better) is:

1. Boot off Xen disk and tell it to convert the current machine to a virtual
2. Xen will install itself as a virtual machine domain with one virtual guest, the original machine
3. Export the virtual machine and import it to its permanent home
4. Configure it in Xen (allocate network etc), boot it, and configure it appropriately.

[SimpleSi]

I've virtulised my old Win98 fileservers when I've introduced w2k3 replacement servers. I then slowly introduce DNS and DHCP run off the w2k3 serveras as an when I want to.

I've found it useful to keep the Win98 virtual machines running as interface print servers for eeePCs.

The eeePCs don't seem to like printing thru w2k3 servers to network printers (keep on asking for passwords when pupils try to print) but are more than happy to print via shared printers on Win98 virtual machine/

regards

Simon

[Butuz]

I am looking seriously into virualisation too Gareth, in particular to start off with virtualising several web / app servers that are old and low spec servers but with a view to eventually virtualising the whole system.

Also I have three terminal servers unfortunatly running off Win2k3 Stanard edition (thus limited to 4GB of ram). I am looking to virtualise all three of these servers into one physical quad core 16GB ram server in order to free up two aditional quad core servers. It may not work - but if it does I have just got myself two free servers effectively!

I suppose the main benefits for me are:

1) Make the most out of existing hardware while reducing support/warranty costs - e.g take 3 old crappy web servers and virtualise them onto an existing hish spec server.
2) Platform independent (take a virtual machine and run it on any server, or even a workstation!)
3) Easy disaster recovery - take snapshots before installing server patches/software, backup whole VM's onto tape/disk/offsite. If your physical server goes down simply install vmware esx on another server or god forbid even a powerful workstation - and hey presto all your virtual servers are back up and running.
4) All the above help to ease managment and critically, reduce downtime.

It's all very exiting!

[Butuz]

Oh well here goes!

I've downloaded VMWare ESXI from the website.
Installed it onto a bog standard Workstation - P4 3.4/3GB Ram/ 80Gb HDD
Set it on the network with a manual IP etc.
Virtualised a test Windows 2003 Web server I had set up to use with Sharepoint.
Hey presto - my web server is now a virtual server, connected to the network and accessible from all workstations!!!
I created a snapshot of it and now i can fiddle to my hearts content and if it all goes screwy - revert bnack to the snapshot!

It was easy to set up! Vmware Convertor is a magic program - how awesome are the programmers behind all this VMWare software?!!

[Theblacksheep]

It was easy to set up! Vmware Convertor is a magic program - how awesome are the programmers behind all this VMWare software?!!

Its very good, very fast now too.

VM-HA looks usefull, if you have ther server overheads.

[sammy]

Hi Gareth ,

you should consider Virtual Iron as part of any virtualisation investigation.

Great product, fantastic pricing. VMWARE is no doubt a great product, and Virtual Iron is just as good but alot cheaper.

Sam