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| 15 Nov '07 - 16:42 | | news source ~ In-House Windows Server 2008 Virtualization and High Availability
Techlog joined a session on TechEd IT Forum presented by Bryon Surace and Mike Sterling about "Virtualization and High Availability". They gave some figures on the time it takes for Virtual Machines to failover from one to another host.
| VM Memory | 1 GbE iSCSI | 2 Gb FC | 4 Gb FC |
| 512 MB | ~8 seconds | ~ 4 seconds | ~2 seconds |
| 1 GB | ~16 seconds | ~8 second | ~ 4 seconds |
| 2 GB | ~32 seconds | ~16 seconds | ~8 seconds |
| 4 GB | ~64 seconds | ~32 seconds | ~16 seconds |
| 8 GB | ~2 minutes | ~64 seconds | ~32 seconds |
Keep in mind though that because you are using clustering, when you migrate a single Virtual Machine using Quick Migration, you have to make the Virtual Harddisk of that Virtual Machine available to the other node within the cluster. This means that within the cluster the Shared hard disk needs to fail-over to the other node. This means that all Virtual Harddisks on that shared disk will start to Quick Migrate too.
During the session we were pointed to 3rd party solutions which can solve this problems. They also mentioned to use a disk per Virtual Harddisk and use mount points to make the VHD's available.
In order to use Quick Migration with the new Windows Server 2008 Hyper-V functionality, you have to make a cluster. Therefore Quick Migration in the Windows Server 2008 standard edition (and probably the standalone Hyper-V server) is not possible. You have to use Enterprise or Datacenter edition in order to implement Quick Migration.
Our sources at Microsoft mentioned that there is also a feature available which can migrate a WWPN from one machine to another, called NPIV. Why this technology wasn't mentioned is unclear. Perhaps this has something to do with the fact that you need 3rd party support for that?