Generation 2 VMs
Traditional VMs emulate hardware such as the Network cards IDE/SCSI controllers, video cards etc. With the introduction of Serve 2012 R2 Microsoft have introduced generation 2 VMs which utilise a brand new architecture whereby the VM will utilise the traditional hardware of the host server without having to emulate the devices. This opens the door to a number of new features such as secure boot and booting off virtual SCSI etc. This is limited to 64 bit Windows 8 or Server 2012 guest VMs and not supported with server 2008 or windows 7 VMs.
Virtual Machine direct connect
Before Hyper-V 2012 to remotely connect to a running guest VM you would have to RDP to the guest in question. This would require that the guest VM in question has an NIC and IP address configured that you can reach. Now with the release of Hyper-V 2012 R2 Microsoft have introduced another method with does not require this and would enable you to remotely manage your VMs that as yet are not live on your network with an IP address. This is an interesting feature which you would connect via the VMbus to manage such VMs.
While the replica feature in 2012 was a great addition for implementing DR scenarios for your virtual infrastructure Microsoft have now gone a step further in Server 2012 R2. You now have the option to have a third replica which in essence means you can have store one copy onsite and push another of the same VM offsite.
In Hyper-V 2012 replication intervals could not be changed and were set at 15 minutes. So even if you had the supporting hardware and network speed you could not reduce this or also have the freedom to extend it to a higher interval. In Hyper-v 2012 R2 you now have the freedom to select replication intervals of 30 seconds, 5 minutes and 15 minutes. Furthermore this will work with an intermittent connection as Hyper-V will watch for 12 missed cycles before it deems failed and thus with the 15 minute interval you can have up to 3 hours of network downtime until it switches to a failed state.
Compression for Quicker migration
Microsoft have introduced 2 new features that you can select to make Migration of VMs faster over the network by compressing the data being transmitted. Obviously compressing the data will have an impact on processing so you will need to ensure that your hypervisor has the resources available to do this. The other option is via SMB Direct where by the memory of the VM being migrated is copied over using SMB. Microsoft recommend when using the latter option that you have 10GB NICs at each end for better performance otherwise the first option to compress the transmitted data.
Live Exporting and Cloning of VMs
In Hyper-V 2012 you would have to power off a VM you would wish to clone or export which in a productive environment can be a difficult task especially if the role in which it is hosting is in constant demand. Now in 2012 R2 Microsoft have enabled a feature which will allow you to backup/export/clone a running VM. This is an amazing new feature and will no doubt make a lot of sys admins very happy.
Resizing VHDX drives online
With Hyper-V 2012 R2 we now have the freedom to expand/reduce the size of a guest VMs VHDX drive without having to shut the machine down. Bear in mind that this can only be done assuming that the guest VM in question was configured to use a VHDx format virtual disk and not the older VHD format drives.
This feature enables one to limit the amount of Disk I/O by limiting the minimum/maximum amount of IOPS each guest VM can peak. This is especially useful when you have a guest VM that is running a disk I/O hungry application that could potentially cause other guest VMs on the same hypervisor to run poorly due to all the resources being absorbed by this disk hungry VM in question.
These are some of the new features for Hyper-V 2102 R2 and we can appreciate how Virtualisation is developing in the IT world. As the virtualisation technology continues to develop we system admins are going to appreciate this technology more and more. No more worrying about tape and bare metal restore backup scenarios we will be in a world where everything is in a virtualised state and can quickly be backed up and restored to another hypervisor