deleting snapshot hangs

[koshimagap]

Have VirtualBox v.4.3.6 running on Windows7ProSP1 x64 host with guest VMs also running Windows7ProSP1 x64.

Routinely create snapshots for backup purposes (e.g., cleanly rollback changes such as failed Windows Update installs) and later delete snapshots when no longer needed with no issue for some time.

However, most recent instance when attempting to delete snapshot, process seems to run as expected presenting dialog showing "merging differencing image {...}.vdi", but when status reaches 9% process seems to hang with percentage no longer incrementing but time remaining incrementing (see attached screenshot)

Have tried upgrading host to VirtualBox v.4.3.12 but with same result when attempting to delete snapshot.

VirtualBox logs do not seem to record any info related to deleting snapshot. Any feedback as to what may be going wrong and how to fix would be greatly appreciated.

[mpack]

You don't mention how big the snapshots are? How much space is available in the Snapshost subfolder?

The only reasons for failure which I can think of are issues with the host: low on disk space, and filesystem or disk sector errors. You would need to check and fix these before the VM can be fixed.

The easiest VM fix would be to restore the VM from a recent backup: meaning a real backup (i.e. redundant copy), I do not mean a snapshot. Did you routinely make real backups as well?

[koshimagap]

VMM showing snapshot to be deleted is ~66GB and current snapshot to be merged into is ~53GB (see attached screenshot) -- local HDD should have ample freespace with over 490GB

Yes, do have true backups (using Acronis) for restoration purposes, but am wanting to be able to reliably create and delete snapshots as differencing snapshots tend to consume lots of diskspace and would fill up HDD quickly if not purged when no longer needed

Does VirtualBox log any info relating to deleting snapshot that might give indication as to what may be going wrong?

[noteirak]

Update to the latest 4.3.x version (4.3.12 as time of writting), there was a bug until 4.3.10 that could prevent big snapshots to be properly merged.
But be aware that snapshots of this size WILL take a long time...

[koshimagap]

noteirak thanks for reply, but as noted in initial post, have tried upgrading host to VirtualBox v.4.3.12 but with same result when attempting to delete snapshot.

You mention "that deleting snapshots of this size will take a long time" -- yes prior successful snapshot deletions did take some time to complete but had not taken longer than hour and there was constant HDD activity throughout snapshot deletion process indicating something was running, but now when status reaches 9% and snapshot deletion seems to hang have left process running for several hours (note in initial post screenshot time remaining shown had incremented up to 2 days 10 hours) and there was only intermittent HDD activity. Is this behavior to be expected?

[noteirak]

I wanted to be sure you stay on 4.3.12 and be informative about this bug in general to any other viewers.
There should be constant hdd activity yes.

Could you attach as zip your VBoxSVC.log file directy after trying again? it is located in %USERPROFILE%\.Virtualbox

[koshimagap]

noteirak as requested please find attached .zip of VBoxSVC.log file.

Attempt to delete snapshot left running overnight but with same result -- deletion appears to run as expected until dialog status reaches 9% at which time process seems to hang (status percentage no longer increments beyond 9% but time remaining increments indefinitely, and constant HDD activity drops off to only intermittent activity)

[noteirak]

I wish the log gave more info... I'm out of ideas to be honest. Unless someone else does, I can only advise you to try 4.3.14_RC1 who just came out, you never know...

[socratis]

Can you post the output of the two commands below? Zip the output if necessary.

dir "C:\Users\KOshima\VirtualBox VMs\Windows 7 Professional x64 GAP\Snapshots\"
VBoxManage list hdds

Remember that you have to be in the VirtualBox installation directory (typically "C:\Program Files\Oracle\VirtualBox\") to run the VBoxManage command.

[koshimagap]

socratis as requested please find attached .zip output of dir and VBoxManage commands.

[socratis]

UUID:           415376df-36c8-4052-b852-db8937aeba56
Parent UUID:    4aca9a00-a731-4a79-bfab-dcd263b51c78
State:          locked read
Type:           normal (differencing)
Location:       C:\Users\KOshima\VirtualBox VMs\Windows 7 Professional x64 GAP\Snapshots/{415376df-36c8-4052-b852-db8937aeba56}.vdi
Storage format: VDI
Capacity:       715366 MBytes

UUID:           684b7727-ee5a-4be0-9302-8ba93e735956
Parent UUID:    415376df-36c8-4052-b852-db8937aeba56
State:          locked write
Type:           normal (differencing)
Location:       C:\Users\KOshima\VirtualBox VMs\Windows 7 Professional x64 GAP\Snapshots/{684b7727-ee5a-4be0-9302-8ba93e735956}.vdi
Storage format: VDI
Capacity:       715366 MBytes

All your snapshots for your GAP guest have "locked read" as their state. Except the last one that is "locked write". Compare them to your other VM; "state: created" (BTW, this is what I have for all my VMs, created). Permissions? Read-only directory?

[koshimagap]

socratis did notice that too from requested VBoxManage output, however have no idea how/why state snapshot state changed.

As far as am aware, both VMs were created same and VirtualBox Manager Settings for both are also configured same. From Windows OS perspective, no VBox folders and files have been changed outside of VBox, and snapshot folders cannot be readonly as both the current and to be deleted snapshots are getting their modified dates and filesizes changed as shown in earlier requested dir output attachment

Any direction as to how to change the snapshot state and impact and meaning of each of these various states would be greatly appreciated.

[socratis]

I just realized what "locked read" and "locked write" means.
THE VM IS RUNNING!
Would you mind shutting it down? Not saved, not paused. Turn it off. Then, try again to delete the snapshot.

[koshimagap]

socratis please find attached second .zip output of dir and VBoxManage commands but with all VMs powered off and VirtualBox Manager closed -- all snapshots now show "created" state which is what is expected, correct?

Should have mentioned that when deleting snapshots, all VMs are always powered off with only VirtualBox Manager running (as snapshot deletions are done from Snapshots window within VBox Manager) after clean reboot of host.

[socratis]

As the green wise man once said:

I'm out of ideas to be honest.

Actually a couple of things that I would try: Run "chkdsk /B" on the host. If that doesn't work and you still hang while deleting the snapshot, I would head to the bugtracker and either search for an appropriate bug where you'll attach your logs and other vital information, or open a new bug report.