Windows Server Core
Microsoft introduced Windows Server Core in Windows Server 2008 and this continues in Windows Server 2008 R2. During the setup of your server you had to choose between the GUI or the Core version. Personally I like the Core version because it’s faster, more secure, needs less patching and so on. However sometimes it was a challenge to configure things within the OS like NIC bindings e.g. Over the time there appeared tools for managing Server Core (see also this and this blog). The command line scares many admins because of the unknown territory of CLI. Windows Server 8 will change this: In Windows Server 8 you can turn the GUI on and off whenever you want. So there is no reason anymore to choose the GUI version for a Hyper-V host. You can run Server Core and when you need to configure something you can turn on the GUI configure your stuff and turn the GUI off again!
Virtual Machines on a File Server
Yes you read that correctly. With Windows Server 8 it’s possible to store virtual machines on a Windows file server! This is made possible through the updated file server protocol SMB 2.2. This means that it is not a requirement anymore to make use of a SAN system when you build a Hyper-V cluster. You can simply point your nodes in the cluster to the file share where the VM is placed. I really wonder how this performs and how reliable it is. However this will give the small sized business the opportunity to easily build a high available Hyper-V environment.
This feature is already announced in the early summer of this year. Because it’s a very interesting feature I will mention it again. Hyper-V Replication makes it possible to replicate a virtual machine to another Hyper-V host without the need for expensive storage hardware and replication software. This even can be a virtual machine that is stored on local storage. The network connection between the host could be a one gigabit Ethernet link. If you have a large virtual machine that would take hours or days to replicate over your network it is also possible to do the first replication to a portable drive. Transfer this drive to the other host, copy the replica to the host and from then only replicate the changes. So this will give you the possibility to implement a disaster recovery site without the need to spend a lot of money.
In Windows Server 2008 (R2) Microsoft does not support NIC teaming but instead directs you to the OEM hardware vendor. This was a great disadvantage and a lot of people has complained about this. Well Microsoft has heard all these complaints. In Windows Server 8 we don’t need NIC teaming software anymore! The Operating System will do the job!!! Great isn’t it? It doesn’t matter if you use two or more different NICs for different vendors. These can all be teamed by the OS. The OS will do bandwidth management, failover management and will also improve throughput.
Domain controllers that are virtualization-aware
Snapshotting a virtual machine with the domain controller role is absolutely unsupported. The restore snapshot method will likely cause a rollback in the update sequence number (USN) used to track changes in Active Directory. When a USN rollback occurs, the contents of the Active Directory databases on the improperly restored domain controller and its replication partners may be permanently inconsistent… But thins will change with Windows Server 8!!!!!
On top of Windows Server 8 you can install a virtual machine with the Domain Controller role and AD will be virtualization aware. It even understand what needs to be done when a DC goes back in time (revert a snapshot). There is even an option DC cloning. When you setup a virtual DC you can make this DC clone-able.
Hyper-V in Windows Server 8 is more scalable then it was ever before:
- In the beta a Hyper-V host support up to 160 CPU cores;
- 2 TB of RAM
- 4000 virtual machines per cluster
- 63 nodes per cluster
Virtual machines will support up to 32 virtual CPU’s and 512 GB of RAM. There also will be a new virtual harddisk format VHDX. VHDX should be faster and can exceed the 2 TB size limit of a VHD file.
De-Duping on storage and network
Windows Server 8 can dedup files within a VHD file. So If you have some VHD files with all a Windows Server 8 installation on it identical files will be deduped to save storage! This will also happen when you copy a number of files between two Windows Server 8 host the network stack will do dedupping as well.