tag:blogger.com,1999:blog-6230024559279811901.post8511826961441147652..comments2023-08-28T14:37:10.715-07:00Comments on I.T. Proctology: Never resize a VHD with snapshots or differencing disks – more about differencing disksBrianEhhttp://www.blogger.com/profile/09946552115562772058noreply@blogger.comBlogger14125tag:blogger.com,1999:blog-6230024559279811901.post-55310805334957622682014-04-21T23:10:06.239-07:002014-04-21T23:10:06.239-07:00FYI, the vhdtool doesn't work on VHDX files. H...FYI, the vhdtool doesn't work on VHDX files. However, I was able to resolve this for a coworker. I made copies of both the vhdx and avhdx, then did an edit of the avhdx, which gave me the only option of reconnect with parent vhdx. I reconnected it to the new copy of the vhdx instead of the original. Then I ran an edit on the avhdx again, and this time was given the normal options of resize, convert, merge. I selected merge, then used the option of merging to a NEW VHDX file. The new file was back to the original size of the disk prior to the resize/snapshot debacle and was fully bootable. I attached this newly created VHDX to the a new VM created with the same settings as the old and then fired it up.Kyle Cnoreply@blogger.comtag:blogger.com,1999:blog-6230024559279811901.post-68033724689876872502011-07-05T22:27:49.378-07:002011-07-05T22:27:49.378-07:00Brian,
Thank you SO MUCH for this info and for me...Brian,<br /><br />Thank you SO MUCH for this info and for mentioning vhdtool. That tool saved our production exchange server tonight. Ok, really it saved ME. I'm on my way over to thank the author now.<br /><br />GaryKDADhttps://www.blogger.com/profile/16511546803925771835noreply@blogger.comtag:blogger.com,1999:blog-6230024559279811901.post-17021931597469242862010-06-26T07:22:57.732-07:002010-06-26T07:22:57.732-07:00Ah, the snapshot is deleted, the data isn't.
...Ah, the snapshot is deleted, the data isn't.<br /><br />The implementation is that you delete the existance of the snapshot (the ability to return to a point in time) not the data of the snapshot.<br /><br />The model that MSFT uses is designed to not lose data.<br /><br />It is the same reason that if you delete a VM using the Hyper-V Manager that you end up with a single VHD left behind. (SCVMM is different - you perform a adelete that and it is all gone). Two differnet products, two different theories.BrianEhhttps://www.blogger.com/profile/09946552115562772058noreply@blogger.comtag:blogger.com,1999:blog-6230024559279811901.post-14384435139552958832010-06-26T06:41:45.533-07:002010-06-26T06:41:45.533-07:00Nice Article.
If the snapshot is just the 'tr...Nice Article.<br /><br />If the snapshot is just the 'tracing paper' (AVHD) why does it have to merge when the snapshot is deleted and no longer needed?<br /><br />GregAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6230024559279811901.post-64516063293381708622009-10-19T12:04:15.069-07:002009-10-19T12:04:15.069-07:00I have seen a very similar issue (the not booting ...I have seen a very similar issue (the not booting issue) seems that a VHD has both a virtual and physical geometry. <br /><br />The physical geometry was the important part that was necessary to get the VHD to boot.BrianEhhttps://www.blogger.com/profile/09946552115562772058noreply@blogger.comtag:blogger.com,1999:blog-6230024559279811901.post-30006474568421064862009-10-19T11:59:06.627-07:002009-10-19T11:59:06.627-07:00I was the guinea pig that tested it for Chris. He...I was the guinea pig that tested it for Chris. He had hoped it would restore the VHD back to its previous bootable state, and while it didn't boot after, I did manage to recover all the data by rolling in the snapshot after the repair. Chris is pretty certain it did not boot because something was done to update it after the size change, which is possible as a third party was working on the issue with me. <br /><br />Thanks a ton Chris!robrhttps://www.blogger.com/profile/06098756988141592986noreply@blogger.comtag:blogger.com,1999:blog-6230024559279811901.post-75912752878153367962009-10-19T11:43:36.303-07:002009-10-19T11:43:36.303-07:00VHDTool.exe on CodePlex has just been updated to s...VHDTool.exe on CodePlex has just been updated to solve this very problem!!<br /><br />Go check it out and sleep a little better (but make those backups!)<br /><br />http://code.msdn.microsoft.com/vhdtoolBrianEhhttps://www.blogger.com/profile/09946552115562772058noreply@blogger.comtag:blogger.com,1999:blog-6230024559279811901.post-91557956408194598592009-10-18T11:33:19.946-07:002009-10-18T11:33:19.946-07:00I understand that if I had a backup of the VHD, I ...I understand that if I had a backup of the VHD, I could use that. I do not have that backup. The IT company responsible for setting up and performing our backups never added the physical server (or any of the VMs) into the backup routine.<br /><br />That being said, I'm working with Chris Eck to repair the damage that has been done, so there may be some light at the end of the tunnel. Huge thanks to Chris for taking his valuable Sunday afternoon to help me.robrhttps://www.blogger.com/profile/06098756988141592986noreply@blogger.comtag:blogger.com,1999:blog-6230024559279811901.post-72116482359887280552009-10-18T11:26:33.863-07:002009-10-18T11:26:33.863-07:00It is rather a difficult process.
If you have a...It is rather a difficult process. <br /><br />If you have any backup that you can return to that matches a point in time that a snapshot was taken, then this can be restored as a previous VHD.<br /><br />I am guessing that the snapshot was condiered the undo tool for resizing the virtual disk? You don't have a back-up as well?<br /><br />Any back-up can be used to restore your system, however your snapshot history is lost, but you would have your system.<br /><br />This goes right along with the statement "don't use snapshots as a method of back-up" - they are not the same thing.BrianEhhttps://www.blogger.com/profile/09946552115562772058noreply@blogger.comtag:blogger.com,1999:blog-6230024559279811901.post-67805879594009581112009-10-17T20:01:28.564-07:002009-10-17T20:01:28.564-07:00Ugh. Guess what I just did... to our Exchange Ser...Ugh. Guess what I just did... to our Exchange Server.... and guess who doesn't have a backup of the original VHD. Is there a company that I can contact has the know how to write a tool to undo what I did? Obviously Microsoft could, but I don't think they do contracting work like this :).robrhttps://www.blogger.com/profile/06098756988141592986noreply@blogger.comtag:blogger.com,1999:blog-6230024559279811901.post-48526504612790280922009-09-15T07:44:37.654-07:002009-09-15T07:44:37.654-07:00There are utilities (not Linux) that have been dev...There are utilities (not Linux) that have been developed that do the block by block comparison in an attempt to create something different.<br />I am unaware of any utility (at this time) that actually does a repair of a differencing disk chain where one member has been modified.<br />And you are right - it is the difference between manipulation at the block level vs. the file level.BrianEhhttps://www.blogger.com/profile/09946552115562772058noreply@blogger.comtag:blogger.com,1999:blog-6230024559279811901.post-38195905268018110722009-09-15T07:16:17.243-07:002009-09-15T07:16:17.243-07:00Is there any linux utility/program to merge these ...Is there any linux utility/program to merge these snapshots. The utility should find the difference block by block and the modified block of orginal snapshot should be patched, something like.<br /><br />Thanks,<br />BalaBalahttps://www.blogger.com/profile/18241450462161826979noreply@blogger.comtag:blogger.com,1999:blog-6230024559279811901.post-43293782650283513712009-04-22T07:56:00.000-07:002009-04-22T07:56:00.000-07:00The only way that I have had luck 'undoing' this i...The only way that I have had luck 'undoing' this is to restore the origional VHD from a backup.<br /><br />Another possibility is to recreate the base VHD if you know the exact size and the exact items that were installed, then you repoint the first (oldest) AVHD to it.<br /><br />If the differences are too great then the disk edit wizard won't allow the join to happen.BrianEhhttps://www.blogger.com/profile/09946552115562772058noreply@blogger.comtag:blogger.com,1999:blog-6230024559279811901.post-91074014364514470332009-04-21T20:35:00.000-07:002009-04-21T20:35:00.000-07:00Of course I expanded a VHD that has snapshots with...Of course I expanded a VHD that has snapshots without realizing what was going to happen. Is there any way to undo this?Eric Stollhttps://www.blogger.com/profile/03834879970126349815noreply@blogger.com