Part 6 - Hyper-V
In Windows 2012, the concept of the private cloud is finally at your fingertips. Long gone are the half baked, half delivered features of Windows Server that promised ‘virtualization.’ VMWare had Microsoft and the rest of the cloud folks well under control – which explains, at least in part, their very unpopular price increase when VSphere 5 rolled out. In their defense, I’ve never seen a popular price increase but I digress. Windows 2012 introduces so many new features into the basic OS that makes it the premiere choice for building clouds. First among them are the new features within Hyper-V – Microsoft’s hypervisor. Without the other features I’ve already discussed in previous entries of this series, Hyper-V would still have gotten mad props for all the great changes they have made. With those other features, MSFT has truly moved the bar and now it will be the other players that play catchup. Again, following along our list of content from TechNet, we dive in and look at the major changes/additions:
- Hyper-V can now do preemption of Virtual Machines based on their priority. This means it can power down, move or suspend VMs of a lower priority when the going gets tough on the hardware resources. This is in addition to the scales and weights you can assign to a VM’s resource use on the host. You would see this happen, for instance, during cluster patching. As production VMs move off a host to other hosts so it can patch, resources start to constrain. By preempting, say, all Developer VMs, we can automatically reduce resource needs on an environment when they are needed to keep production (or critical) apps up and running.
- Live migration and Hyper-V replica – one got a great upgrade, the other is brand new. Live migration now has the ability to queue up moves. This prevents you from overtaxing IO, network bandwidth, etc when things need to move right now. On the replica side – this allows you to have a bit for bit replica in place at your secondary site, ready to take over responsibilities should your primary site fail. It can also magically change IP addresses if it has to actually boot up (as secondary sites tend to need). The best part is – once you have a copy going, it stays in sync!
- PowerShell – in case you were not already aware, you can’t hardly get to a good ol CMD prompt in 2012 (you can but you gotta go hunting). Hyper-V is now 100% PowerShell friendly with a full vocabulary of support. In fact, the entire OS is. Who needs a GUI? Well…I do, but it certainly makes repetitive processes easier!
- Smart Paging – it took me a while to get this one under my cap, but after reading this excellent entry I now get it. Smart Paging comes into play when you are restarting VMs and because of Minimum RAM settings introduced in 2012, you may not have any resources. So, Smart Paging creates a special paging file within the VM structure to let it boot, then dumps that file. Keeps you from deadlocking on restarts. Note – has no impact on starting a VM, just restarting.
- Hyper-V network virtualization – serious stuff here, from SR-IOV support to the new extensible switch. The basic idea here is profound yet simple – the entire networking stack has been rewritten to be virtual aware and performant at the hardware level. Saw a demo at TechEd where they moved a 10 GB file from one VM to another VM in 10 seconds…oh yeah. Of course, that also took advantage of ODX (offline data transfer support) but still – the ability to do things to the network tier is quite impressive.
- If you are in the reselling business (or chargeback), Hyper-V now has support for resource metering, meaning you can quickly generate reports on how much ‘stuff’ a VM is consuming and charge for it appropriately.
- Support (just like the parent OS) for 4KB sectored disks – good stuff.
- Direct MPIO based iSCSI and Fibre Channel pass through support. Makes for some wicked cool highly available clustered VMs.
- Hyper-V’s new file format – VHDX – supports 64Tb disks, ability to protect against corruption, 4KB sector support, larger block sizes, works (finally) with TRIM and allows for custom metadata. The end result? No real need to do pass through disks just cause the data is large!
- Hyper-V now ships with a virtualized switch which is great because it increases the security footprint as well as flexibility to do things like spans.
- VMs can now have up to 32 processors and 1 TB of RAM and it doesn’t cost extra money to do it!
- Hyper-V storage migration allows you to move your underlying storage around for whatever reason while the VM is running.
- The OS provides native support for cross brand based NIC teaming and that capability is also provided to the VM – which means getting serious throughput to your VM (50-60GB/sec?!!!!) is pretty trivial.
- Hyper-V live migration no longer requires a cluster. Supports SMB based file shares. Supports Cluster Shared Volumes. Supports Storage Spaces. Supports Shared Nothing configurations. Holy bananas!
- Ability to move a VM around to other clusters without exporting and importing. When you go to add an existing VM to new hardware, there are 40 some odd checks that get run to make sure that the VM you are attaching is ready to rock and roll.
Other than that, pretty boring stuff. HA