Powercut reverted VM to previous state
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30 สิงหาคม 2553 19:08
Hi
I have Windows 2008 Enterprise Server running Hyper-V.
I have several VMs running on it.
There was a powercut over the weekend which resulted in the machine being ungracefully switched off.
On restarting the machine, we found out that one of the VMs was reverted back to a state a few months ago which means we lost all changes since then to now.
Kindly advise if this is a bug or if some changes are to be made to ensure that this does not happen again.
Thanks in advance.
- Andre
ตอบทั้งหมด
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30 สิงหาคม 2553 19:56ผู้ดูแล
All that happened was that the host shut down and the host was powered back up?
It sounds as if snapshosts were involved and somehow the VM was re-configured to use it root VHD not the snapshot AVHD.
Was any type of restore from backup involved in recovering the host, SAN, etc.?
In other words no, what you describe should not happen on its own. However, I have seen many cases with this type of results and frequently it involved some type of reconfiguration, recovery, or loss of snapshot disks.
Brian Ehlert (hopefully you have found this useful) http://ITProctology.blogspot.com -
30 สิงหาคม 2553 19:59
Note that it was not a graceful shutdown - it was a powercut.
How to configure to use AVHD instead of the VHD.
No restore was done - that physical server was then powered up and the VMs started.
Default settings are used.
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30 สิงหาคม 2553 20:13ผู้ดูแล
Nobody did any type of reconfiguration of the VM settings?
Then a couple more questions: Did the VM have snapshots that were previously deleted (but the VM was never powered off)?
Also, when you say the VM was reverted to a previous state. What exactly do you mean?
Brian Ehlert (hopefully you have found this useful) http://ITProctology.blogspot.com
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30 สิงหาคม 2553 21:32
No reconfiguration was done.
No Snapshots.
"VM was reverted to a previous state":
Let's say in March I installed the base OS of the VM (Windows 2003 server for example). Then in May I installed a HelpDesk Application on the base OS of the VM.
When the power was cut and I start the system, the base OS from March is there but the HelpDesk application is not there.
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31 สิงหาคม 2553 7:22ผู้ดูแล
Hi,
If there are no snapshots with the problematic VM, the issue may cause by the basic operating system instead of Hyper-V. It seems that there are some restore points within the problematic VM, it restore the system to a previous state after the restart from the powercut.
If you don’t have the backup for the VM, I don’t think you can get the lost data back. However, you may also wait for other customer's experience sharing on this.
Vincent Hu
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31 สิงหาคม 2553 12:47
Hi Vincent
I have to disagree - restore points do not work automatically - you have to manually restore to any restore point.
I have never had a problem like this except in a Hyper-V environment.
I hope this "bug" has been fixed in the R2 version.
- Andre
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7 กันยายน 2553 6:29ผู้ดูแล
Hi,
Did you use differencing disk with the problematic VM?
If you did not have either a differencing disk or a snapshot involved, I don’t see how that situation could ever occur. If there is only a single, master disk, it has to be writable – otherwise they would receive an error when trying to start the VM. The only way the master disk is not being written to is if changes are being written to a differencing disk or a snapshot.
Vincent Hu
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18 พฤษภาคม 2555 11:28
Hi,
Unfortunately we have reverted one of our VM to old Snapshot,
We don’t have new Snapshot. Is there any chance that we can recover our running VM up and running. Please help in this. Thanking you in advance.
Thanks & Regards
Kishore Varanasi
+91 7893226226
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18 พฤษภาคม 2555 14:22
I have to agree with Vincent. There is absolutely no way for a machine to revert to an earlier state unless there is an earlier to available to revert to. Earlier states can only be available via snapshots or differencing disks.
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