Last week we were scheduled for a Major power failure and had to power down our Host Hyper V Windows 2008R2 servers for the first time.
We manually shutdown all guest vm's then powered down each of the host.
Now when we powered up the host and the the guest, we noticed the following problems.
SQL server could not send mail using sql mail, and users could not communicate with client server applications, where the server-side was on the guest.
After various of hours of troubleshooting, we decided to remove each of the guest's and re-add them again; basically deleting the guest from the hyper-v management window, and recreating it using the same virtual hard drives, and this fixed the problem.
Out of curiousity we tried the shut down process again, and encountered the same problem, applied the delete add fix again and it fixed it.
My question is do you know what the cause is? do we have to do this anytime we have to power-down the host? (this will in no way be often, but with murphy's law in place, who knows?)
A little background although I don't believe it's relevant, the vms were created using the disk2vhd tool a couple of years ago and have run fine with no problems until this shutdown of the host.