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We are planning to add a virtual disk to an existing "windows 2008 R2" domain controller.

The new disk will act as a fileserver for the domain.

(The administration said we should do it this way to save a licence and the additional cpu overhead.)

I believe this new virtual disk for the fileserver shares should be added as "independent persistent" disk. Is this correct? The question is, if the data on the independent disk be safe, in case we take snapshots of the VM? Even if we roll back snapshots.

EDIT - to eplain the simple VM setup :

We have already disk1, which is the system disk with c:\windows and all the programms and c:\users and it will stay a standard vmware "dependent" disk.

Only the new disk2, which will be the fileserver disk will be "independent persisstent". Disk2 will be a windows share that all the users can put their files on.

In case of a snapshot this should do the right thing, shouldn't it? If I take a snapshot today and in 2 days revert to it, this way the system disk will go back in time, but the fileserver disk2 will not.

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This question appears to be off-topic because it is about a subjective question and discussion. Specifically your answer is provided along with the question, and you expect more answers: “I think I should do this...what do you think?" You may consider asking this in chat and someone may offer their opinions there. – TheCleaner Sep 10 '13 at 17:41
I have never in my life had CPU overhead be of any concern on a DC or fileserver. Unless you're serving a huge number of clients, and by the sounds of it you're nowhere near needing to worry about that. – ThatGraemeGuy Sep 10 '13 at 19:19
You should never snapshot a DC… – Zypher Sep 11 '13 at 17:03
up vote 10 down vote accepted

This borders on opinion but I feel pretty strongly about it - never use a Domain Controller as a file server. Create another VM. Once it's a file server you greatly increase the risks of viruses, you can't shut it down with out impacting file sharing services (where AD and other likely services such as DNS should be redundant on other DC's).

DC's should be one trick ponies as much as possible.

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I'd second this. Adding a file server role to your virtual DC very much ignores some of the major reasons for virtualising in the first place. Splitting these workloads allows you to balance them better over your host hardware, and also allows you to perform maintenance tasks on one role without interrupting the service provided from the other (e.g. you can install a file server patch that requires a reboot without bringing the DC 'service' down). – RobM Sep 10 '13 at 19:20
I'll run DNS along with a DC, but I think that's about it. – Michael Hampton Sep 10 '13 at 19:35
Agreed @MichaelHampton - some services go together... I wouldn't even rebel at the idea of a smaller site running DHCP on the DCs as well, but yes, that's about it. – RobM Sep 10 '13 at 20:06
DHCP, DNS and a few other things (CAs) make sense. But nothing that's not on the Windows CD should be put on a DC IMO. That includes pictures of your boss's dog. – TheFiddlerWins Sep 11 '13 at 14:02
@all I appreciate very much your information, it is indeed helping me with my problem. But it seems it is not welcome on SF to ask the qustion the way I did in the beginning. That's why I focussed the question more on the "technical solution part" now. – Alojz Janez Sep 11 '13 at 17:12

In regards to Independant Persistent, please read this article by Cormac Hogan. What is your intended goal for using this setting? You would effectively be disabling snapshots on the virtual disk which may impact your backup, replication, or other operational tasks.

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I have read through your linkm thank you. I am updating the question to make the setup more clear. We habe disk1 which is system disk and will be "dependent" and only disk2, which is the the fileserver disk will be "independent persisstent" – Alojz Janez Sep 11 '13 at 17:01

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