VMware Communities: Disk Error on Fusion Beta 3

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9 Replies Last post: Jun 6, 2009 11:36 AM by NickDePasquale

Disk Error on Fusion Beta 3

May 16, 2007 3:59 AM

Brad Leggat 7 posts since
Jan 25, 2007

Please help, Urgently need to recover some data from Virtual Disks.

I have an XP VM with two Virtual Disks, and I took 1 snapshot about 3 months ago.

Suddenly today, when starting VM, I get an error message :

"Cannot open the disk ...0001.vmdk"
"Reason: The parent virtual Disk has been modified since the child was created"

I did nothing out of th ordinary to modify the parent disk.

Is there any way to fix this, or to recover new data off the disks since the snapshot?

Any help appreciated.

Thanks in advance, Brad

Reply Re: Disk Error on Fusion Beta 3 May 16, 2007 7:39 AM

etung 11,023 posts since
Oct 15, 2006 VMware

The first thing I would do is make a backup of all of the VM's files.

Does it actually say "...0001.vmdk" or is that you editing for privacy? If it's the actual message, before you start fiddling with the disks, you might want to check the vmx and files.

Having done that, this thread may help - you may be able to change the vmdk files to make Fusion think the parent hasn't changed and hope that it hasn't actually changed that much. Then copy all the data off, check it, and start with a fresh VM since you don't know how badly the original is corrupted. Also try searching in other forums, since this isn't Fusion-specific.

Reply Re: Disk Error on Fusion Beta 3 May 16, 2007 11:48 PM

Brad Leggat 7 posts since
Jan 25, 2007

Thanks "etung".

I would like to try change the dates on the origninal disk file to "fool" fusion into thinking that it has not been modified. I am fairly sure that the contents of this disk have not actually changed.

Any ideas which file date should I attempt to change (e.g. "Last Opened" or "Modified"),

and to what actual date? (e.g. the day before it crashed, or the original create date, or ...?)

The link to that post doesnt specify this detail.

Incidentally there are still some .lck files hanging around. Removing them makes no difference.

Reply Re: Disk Error on Fusion Beta 3 May 17, 2007 1:59 AM

Brad Leggat 7 posts since
Jan 25, 2007

I have tried changing the file dates. Does not seem to work.

e.g.
Changed Original Disk MODIFIED Date/Time
to Snapshot Disk CREATED Date/Time

no luck...

Brad

Reply Re: Disk Error on Fusion Beta 3 May 17, 2007 6:37 AM

in response to: Brad Leggat

etung 11,023 posts since
Oct 15, 2006 VMware

The timestamp is actually in the vmdk files. At least for 2GB sparse files, there's a small plaintext metadata file and a (set of) large binary data file(s). The metadata file has fields called "CID" and "parentCID" - what you want to do is make sure the parentCID of the snapshot matches the CID of the base disk. I'm not sure what you'd do for monolithic files (which yours sound like), I can try to do some more digging later.

In the meantime, the following links may be helpful:
http://www.vmware.com/community/thread.jspa?messageID=520002
http://www.ozvms.com/content/view/159/
http://www.google.com/search?q=vmdk+CID+parentCID

Reply Re: Disk Error on Fusion Beta 3 May 21, 2007 5:51 AM

Brad Leggat 7 posts since
Jan 25, 2007

Thanks to "etung", problem solved.

Used hex editor to edit large disk file "....0001.vmdk". Changed parentCID to match CID of base disk.

VM started Ok, data recovered.

Reply Re: Disk Error on Fusion Beta 3 May 21, 2007 6:58 AM

in response to: Brad Leggat

etung 11,023 posts since
Oct 15, 2006 VMware

Cool, glad to hear it worked. You should probably create a new VM instead of continuing to use the old one, because who knows what's wrong with it. If this happens again or you figure out what triggered this, please let us know.

Reply Re: Disk Error on Fusion Beta 3 May 21, 2007 7:07 AM

Brad Leggat 7 posts since
Jan 25, 2007

I have figured out how I got the VM into this state:

While the VM was running, I renamed the Folder containing it's files.

I then suspended the VM, which it could not do. Fusion then "hung" and had to be "Force Quit"

This gets the snap & the base disk out of synch.

One moral of the story: dont keep a snapshot for longer than you really need it. i.e. "Revert" or "Discard" as soon as the reason for the snap no longer exists.

Reply Re: Disk Error on Fusion Beta 3 May 21, 2007 7:15 AM

in response to: Brad Leggat

etung 11,023 posts since
Oct 15, 2006 VMware

Good detective work - I suspect the problem was moving the folder while the VM was running; I've moved around powered-down VMs with snapshots without problems. Please file a bug about this.

Edit: Was the failed operation a suspend or snapshot? I just want to be really clear about what went wrong. -etung 2007.05.21 10:15

Reply Re: Disk Error on Fusion Beta 3 Jun 6, 2009 11:36 AM

in response to: etung

NickDePasquale 1 posts since
Jun 6, 2009

Hello... I picked up this thread and helped me fix an issue i was having. So, thanks many moons later! Nick

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