This post talks about VMware’s DPM. DPM is a cool feature of VMware’s solution. When host server utilisation is low, vSphere will VMotion VM’s to fewer host servers. This is possible thanks to VMFS, VMotion and RAM oversubscription. Idle host servers with no VM’s are then powered off. That could potentially save a fortune in electrical costs. When host server resource utilisation increases then those powered off servers are powered up automatically as required. VM’s are relocated to spread the resource utilisation load.
Windows Server 2008 and Windows Server 2008 R2 Hyper-V do not have this. I can see how it could be done using OpsMgr and VMM 2008 R2. Windows Server 2008 R2 has Live Migration (VMotion) and Cluster Shared Volume (aka CSV or VMFS). However, Hyper-V does not have RAM oversubscription. It was in the early feature list for 2008 R2 last year but MS had to pull it because it wasn’t ready. I know from talking to others that this is a highly desired feature so it won’t surprise me to see it in Windows Server 8.
Windows Server 2008 Hyper-V approaches power savings from another direction by consolidation resource usage in the server, rather than across the server farm. Honestly, I’d like both. 2008 R2 includes Core Parking. When the host OS notices idle CPU cores, they get powered down and the work load is consolidated to fewer cores. Powering down the cores/CPU’s saves CPU power utilisation, reduces heat generation, reduces fan power utilisation and reduces air conditioning power utilisation.