Choosing VM roles in Hyper-V

Posted on 2014-10-26
Medium Priority
Last Modified: 2014-10-29
My trusty single server is 5 years old with a single S2008r2 VM on ESXi with application services, file services, DNS, DHCP, and Active Directory Domain Services roles for 25 clients and 17 users in a medical office. We have backup covered, but want to add a new server and use replication for failover back to the old server. Both servers would be S2012r2 hyper-v hosts.

So my only domain controller has been virtual and we haven't had any problems, but I would like some advice for how to configure each Hyper-V host.

My research says the host should be off of the domain, have only the Hyper-V role enabled, and I will have a backup app there. I am guessing that I will need a VM for DNS, DHCP, and Active Directory Domain Services, and another for file and application services.

For my applications, I have a Sybase advantage database that gets the most users, and 3 sql server express databases. Should those be split into separate VMs so that sql server has it's own? Is it worth buying 2 extra 2012r2 licenses for the two hosts to have 3 VMs each now vs upgrading later if needed? Does it affect backup?

Appreciate your small business modified best practices advice.

Question by:Daniel Watrous
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Expert Comment

ID: 40405567
If you are going to have a HyperV fail over you need to have at least 3 physical servers. two running Hyper v and the 3rd storage This means all the VM.s are stored on the Storage serve and the Hyper V server can access the VM's on the storage. Hyper v servers should be identical as well.

Host definitely not on the Domain . (if DC is turned off you can authenticate to the Hyperv).

If you are going to run it in a true fail over you need really good speed on your storage and a very fast link eg 10 GB as all the Vm's will be sharing the same link. As for SQL express I would not bother separating as its limited to 1 GB ran and 1 cpu anyway  make sure you have enough ran and cpu for all SQL.

It gets expensive quite quickly especially if you need speed. Since you are talking about reusing your old hardware why not consider  1 new beefy server and using Something like shadow protect head-start restore to your old server. That way if it crashes you can just boot up the old server and it will be a few minutes behind the crashed one. Good product and we have had great success with.

LVL 24

Accepted Solution

VB ITS earned 2000 total points
ID: 40405698
What Aremenio is describing above is implementing a Hyper-V High-Availability Cluster, although he's is incorrect when he says the host should not be domain joined. The host must be domain joined in order to create the Hyper-V failover cluster as described in the General (Host) section here: http://blogs.technet.com/b/askpfeplat/archive/2013/03/10/windows-server-2012-hyper-v-best-practices-in-easy-checklist-form.aspx

As he mentions above, creating a Hyper-V failover cluster can get expensive very quickly, especially when you factor in the costs of SANs, switches, etc.

I think two VMs will suffice for you on a single host. You can use a single Windows Server 2012 R2 Standard license as well to save money as one license will allow you to bring up two 2012 R2 VMs, as long as the you only use the host as a Hyper-V host, i.e. you can only install the Hyper-V role on the server to manage the virtual machines and nothing else. Download the official Windows 2012 licensing brief here: http://www.microsoft.com/licensing/about-licensing/briefs/win2008-virtual.aspx

Pages 3 and 4 will describe the above in more detail.

A lot of this will come down to, as always, the budget of the SMB. Can they afford two high end servers, a SAN device,  and multiple switches? Or will a single physical server suffice?

Expert Comment

ID: 40407579
My bad (Sorry VB ITS) I was going off my bad memory you are right with the host being in a domain . Just make sure its a separate domain and not in any VM. I recommend both Hyper v server be Domain Controllers

"Domain role   All servers in the cluster must be in the same Active Directory domain. As a best practice, all clustered servers should have the same domain role (either member server or domain controller). The recommended role is member server. If the clustered servers are member servers, you need an additional server that acts as the domain controller in the domain that contains your cluster."

Take a look at the Shadow protect solution its really good and cost effective and will give you near instant fail over 10 -15 min to bring the system back up. ( Ps.I don't work for SP but have been using their product and it has saved my ass on more than one occasion)

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