dbndtl
Contributor
Contributor

Unable to revert to snapshot after expanding disk

Yesterday I attempted to upgrade a virtual Windows Server 2003 server to 2008 to

overcome a Windows 7 client to Windows 2003, Printer disconnections issue.

Prior to the upgrade I took 2 snapshots and ran

upgrade however as I then needed more disk space on the primary disk to install Server 2008 we used a disk

re-sizing method that has been used before: remove the hard disk from

the 2003 virtual machine – add it to a 2008 server VM.

Then expand the disk in the 2008 server before removing and re-adding

to the 2003 server VM.

The 2008 installation failed (long story which I wont go into unless needed) and I tried to revert to the snapshot

and got error:

Cannot open the disk

‘path to the .vmdk file’ or one of the snapshot disks it

depends on.

Reason: The parent virtual disk has been modified since the child was

created’

I read through the following link:

http://communities.vmware.com/message/744516

In here it mentions:

In

current versions of ESX Server 3, do not extend a disk that has

snapshots. Commit or discard snapshots before increasing the size of the

virtual

disk. Extending the size of a virtual disk that has snapshots will

invalidate the snapshots. This issue is being investigated for a fix in a

future release.

I tried to go through the solution and found the error below in the vmware.log file:

"...Opened

'/vmfs/volumes/4a8405d5-a8045771-f87e-0024e8713921/ruth.oakhill.ac.uk/ruth.oakhill.ac.uk.vmdk'

(0xe): vmfs, 115208142 sectors / 56254 Mb.

*Jun 08 00:23:26.760: vmx| DISKLIB-LINK : Attach: the capacity of each

link is different (115208142 != 71167950)..."*

I thought I may be able to edit the # Extent

description part of the code as advised in above link but got stuck at the ddb.geometry.cylinders as I am not sure how to work this out.

Currently I have a live environment / site down due to this issue so would appreciate any assistance with this.

Thanks,

Dan

5 Replies
firestartah
Virtuoso
Virtuoso

Hi

Having done this exact thing before i have to warn you that before you follow these steps I can't promise you will get your snaphot data back nor can i promise it won;t sorrupt your vm but having done this process with vmware support a few weeks back this is what they would make you follow also.

First is make a clone of the machine we're trying to fix just in case

Next is the fun part due to you expanding the drive and therefore the snapshot has a different RW value than your vmdk.So you need to use putty and edit the “VirtualDisk.vmdk” file in notepad and look for

RW *number* VMFS “VirtualDisk-000001-delta.vmdk” .

WRITE THE NUMBER AFTER RW DOWN.This one is what the drive was before the expand

Next open the “VirtualDisk.vmdk” file and look for the RW *number* VMFS "VirtualDisk-flat.vmdk" value. What we are going to do is make it look as if the expand never happened. So edit the “VirtualDisk.vmdk” file and put in the FIRST number from the “RW *number* VMFS “VirtualDisk-000001-delta.vmdk” into the VirtualDisk-flat.vmdk line and save it.

Secondly one of the problems could be down to your CID for your VMDK being different from your snapshot/s so follow this http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=100522...

After making sure the CID's match then "delete" the snapshots. If your snapshot manager shows no snapshots then create one called test or whatever you like, let it create, then go to snapshot manager and click delete all and this should apply/"delete" the snapshots

=0) I blogged this work around if you are interested http://thesaffageek.wordpress.com/2010/06/22/expanded-disk-with-existing-snapshot-corrupted/

If you found this or other information useful, please consider awarding points for "Correct" or "Helpful".

Gregg Robertson, VCP3,4 , MCSE, MCSA, MCTS, MCITP

If you found this or other information useful, please consider awarding points for "Correct" or "Helpful". Gregg http://thesaffageek.co.uk
dbndtl
Contributor
Contributor

Thanks for the response and this is good to know I was on the right track, only problem I currently have is: the vmdk file is on a NAS box in a datastore and 50GB so it takes so long to copy over to a hard drive for me to edit the header information. Or maybe I am not doing this correctly as I though putty was for access the ESX command prompt only?

Will let you know,

Thanks,

Dan

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firestartah
Virtuoso
Virtuoso

You shouldnt need to copy it over? You should be able to edit it via winscp. Yeah you can do searches via putty to give results but my linux command skills arent very strong so didn;t want to give you the wrong info.

If you insist on copying it over try fastscp. It's a brillaint free tool by veeam for copying over large vmware files ten times faster than normal scp tools do

http://www.veeam.com/vmware-esxi-fastscp.html

If you found this or other information useful, please consider awarding points for "Correct" or "Helpful".

Gregg Robertson, VCP3,4 , MCSE, MCSA, MCTS, MCITP

If you found this or other information useful, please consider awarding points for "Correct" or "Helpful". Gregg http://thesaffageek.co.uk
dbndtl
Contributor
Contributor

Thanks for your help on this problem, I am still working on it unfortunately, coming up to 24hrs straight with only a couple of hours kip (arhhh). I am sure this would have helped but I did not get chance to try it out as the vmdk files have disapeared from the datastore, really at a loss as to how it happened but we have been working on it so long and tried so many things concurrently it could have been a few things.

Currently I am rebuilding from a tape backup so will see how that goes...(only thing left at this time)...

Thanks again,

Dan

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continuum
Immortal
Immortal

Is this still hot ?

to expand a snapshot so that it works again with an expanded basedisk you usually do not need to copy files around ...

guess this is already solved differently ?




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