Does it really matter if all my DC's are virtual?

[edutech4schools]

I know MS say you need to have at least one physical DC but would the following scenario get around this.

 

I am setting up a hyper-v host for a small primary school with 1 VM having DC+DNS on and the other VM having data etc. This host will not be domain joined.

 

I have a second older server that I was told I should install as a physical server with DC+DNS but this does seem like a massive waste of a server and I would really like to visualizer this server and run a few other things including a second virtual DC+DNS

 

How much of an issue is it if I do not use the old server as a physical DC server? but run this older server as a second host with a second vm DC?

 

Does the fact I was not going to add the host servers to the domain make a difference?

Edited March 16, 2015 by edutech4schools

[snagrat]

Do MS say to have one physical?

 

I know they used to due to clustering limitations but now with Server 2012 R2 that is no longer the issue I thought

[3s-gtech]

I don't believe that they do say that any more.

 

It's a bad idea to have only virtual DCs hosted on a single domain joined Hyper-V host (goes without saying really). If you can spread them about so they're not entirely dependent on the domain (I have one on ESXi) that'd be a bit more reassuring.

[edutech4schools]

It's a bad idea to have only virtual DCs hosted on a single domain joined Hyper-V host (goes without saying really).

But why?

 

Some have said it could be an issue if the virtual DC went down because the host would have issues logging onto the domain as it would need the virtual DC to be running before the host booted up, which obviously is not possible, but my hosts are not going to be domain joined, so is that still an issue?

[sparkeh]

But why?

 

Some have said it could be an issue if the virtual DC went down because the host would have issues logging onto the domain as it would need the virtual DC to be running before the host booted up, which obviously is not possible, but my hosts are not going to be domain joined, so is that still an issue?

Personally I run my hosts as standalone machine even though you *could* make them DCs with 2012, just makes more sense to me.

I no longer have physical DCs as I don't think that they are needed but others on here go hopping mad when I mention this

[Achandler]

To explain as best as possible:

 

The real issue is to do with central storage and having your virtual hosts as a cluster. If you have a HyperV cluster, then HyperV had to be on the domain (in 2008R2 atleast) and you had to be able to login to boot the Cluster Service online. Without the cluster serivce online you can't boot a virtual DC, and you can't get the cluster service onlien because you can't login. It forms a catch 22 situation.

 

If you have HyperV hosts that are entirely independent then you can have just vrirtual DCs, it is just against best practice or at least use to be. But it would work fine.

[3s-gtech]

But why?

 

Some have said it could be an issue if the virtual DC went down because the host would have issues logging onto the domain as it would need the virtual DC to be running before the host booted up, which obviously is not possible, but my hosts are not going to be domain joined, so is that still an issue?

 

Precisely. My hosts are domain joined, so could cause problems (not insurmountable though). If yours aren't on the domain, no worries.

[jmak]

So should I want to run a single virtualized DC, the advice would be to not have the host on the domain? And in that scenario, how would I administrate the host machine? I was thinking of using RSAT from a client on the domain, but presumably that only works for machines on the same domain? Or have I got completely the wrong end of the stick?

 

Sorry for asking so many questions on someone else's thread...

[Achandler]

Shall I muddy the waters further?

 

If you have 1 physical host using the host physical storage, with 3 or 4 virtual computers for example then the host can be on or off the network. As you can login locally to the host and start each VM manually, then you can admin them through a network account too.

 

The issue stems around where virtual machines are stored, if they are on storage that requires network access then you need a physical or standalone DC.

[win]

Whatever the logic is, DC's aren't that demanding (resource-wise) so it shouldn't break the bank just to add a physical DC somewhere on an old server. I've got both phy + virtual, the phy being an old server that is still going after many years.

[DavePa]

We run with virtual DCs that sit on non-domain joined hosts. Each site has the local DC for DNS and also a DC located at a secondary site. The DCs are setup to boot immediately the hossts are started, any other virtual servers (file/print, SQL, Impero etc.) are staggered at 30 second intervals. Been running that way for 5 years - some are still 2008r2 machines - without any problems so far although I've probably just guaranteed a failure...

[edutech4schools]

also a DC located at a secondary site.

I really like this idea. I look after a few primary schools and they are all accessible using an IP address.

 

What would I need to do at each site to get a second DC working but located at another school. I assume I would need to do something with DNS at each site so the server at the remote location can access the network at it's real school.

 

Do you have any notes or info?

[daneil16]

I have one physical DC and all others are virtual. Makes sense in case the big boy decides to keel over in the middle of the night at least there is one available DC when you come in after all the early birds.