Scared by snapshots

[ianxxx]

Hi,
I use VirtualBox mainly because I need to make snapshots to test scripts results and get back to the status before the run of the test.
Mine is an Ubuntu 14.04 virtual machine managed with VirtualBox 5.0.14 r105127 running on Windows 10 host.

What is in your opinion the more reliable version of VirtualBox regarding snapshots? (or maybe another software?)

I ask this because the more I use VirtualBox, the more it advances in versions, the more I get errors managing snapshots.
I'm at the point that I'm really scared to take a snapshot while, imho, working with snapshots should be a safe thing for a virtualization software.

Thanks in advance for any kind of help!

[michaln]

What errors exactly?

[ianxxx]

What errors exactly?

During the time I used VirtualBox I had many and different errors.
The last one is a laconic "Result Code: E_FAIL (0x80004005)" when I tried to delete a snapshot, nothing else also in the log.

Btw, the problem is generic about managing snapshots with VirtualBox. It's more the time wasted on trying to fix snapshots errors than the time that should be earned.
And it looks like that this problem gets more evident the more VirtualBox development advances. That's why I'm asking for a reliable version to stick with.

[klaus]

Odd. There haven't been many changes in the snapshot code actually (besides a few rather selective bug fixes, I remember fixing a lost error message, but can't remember if it was when deleting snapshots) over the last years. Not aware of widespread problems with snapshots for quite a while. There was a big restructure of the code before releasing 5.0 (to address a long standing API design flaw), but the few regressions this brought should be fixed by now.

Don't take that as an indirect "use 4.3" advice, because that wouldn't be future proof at all: the support for 4.x ended in December 2015.

[mpack]

I would not use snapshots, but there's no reason to be scared: just make sure you have backups, and don't ever confuse snapshots with backups.

[ianxxx]

Thanks for your answers.
I just had another problem trying to delete a snapshot

Failed to delete the snapshot d of the virtual machine Ubuntu.

Storage for the medium 'D:\VirtualMachines\Ubuntu\Snapshots/{aa9328fc-8011-47af-b7be-4b0121d5f6be}.vdi' is being deleted.

Result Code: VBOX_E_INVALID_OBJECT_STATE (0x80BB0007)
Component: MediumWrap
Interface: IMedium {4afe423b-43e0-e9d0-82e8-ceb307940dda}

[mpack]

"Failed to delete" doesn't tell me a lot. Is that the complete error message?

In my last message I mentioned the importance of backups. Hopefully you took me up on my advice.

[ianxxx]

"Failed to delete" doesn't tell me a lot. Is that the complete error message?

Yes. I think that VirtualBox got stuck in some way because after I restarted the host I was able to delete the snapshot.
I add that when the host was shutting down to restart it complained that VirtualBox didn't want to close, so I had to force the closure.

In my last message I mentioned the importance of backups. Hopefully you took me up on my advice.

I have my backups, that's not the problem. The problem is that a feature like snapshot should be a time saving but with these errors it becomes a time wasting.

[ianxxx]

Again... another error right now:

Code: Select all

Failed to delete the snapshot d of the virtual machine Ubuntu.
Result Code: E_FAIL (0x80004005)

Last lines of vbox.log

Code: Select all

46:02:28.153083 Console: Machine state changed to 'Paused'
46:02:28.239283 GUI: UIMediumEnumerator: Machine (or snapshot) event received, ID = a048b75b-05e9-4046-bba5-28348177d106
46:02:28.239349 GUI: UIMediumEnumerator:  Old usage: 0cbdf686-2e0d-4d71-9ad2-63d679d844d6
46:02:28.242288 GUI: UIMediumEnumerator:  New usage: 590da495-7c65-4cb7-8c02-01d46a111bdc
46:02:28.242314 GUI: UIMediumEnumerator:  Items excluded from usage: 0cbdf686-2e0d-4d71-9ad2-63d679d844d6
46:02:28.242322 GUI: UIMediumEnumerator:  Items currently in usage: 590da495-7c65-4cb7-8c02-01d46a111bdc
46:02:28.248032 GUI: UIMediumEnumerator:  Medium with key={590da495-7c65-4cb7-8c02-01d46a111bdc} cached
46:02:28.248170 GUI: UIMediumEnumerator: Machine (or snapshot) event processed, ID = a048b75b-05e9-4046-bba5-28348177d106
46:02:28.248197 GUI: UIMediumEnumerator: Machine (or snapshot) event received, ID = a048b75b-05e9-4046-bba5-28348177d106
46:02:28.248236 GUI: UIMediumEnumerator:  Old usage: 0cbdf686-2e0d-4d71-9ad2-63d679d844d6, 590da495-7c65-4cb7-8c02-01d46a111bdc
46:02:28.251117 GUI: UIMediumEnumerator:  New usage: 590da495-7c65-4cb7-8c02-01d46a111bdc
46:02:28.251150 GUI: UIMediumEnumerator:  Items excluded from usage: 0cbdf686-2e0d-4d71-9ad2-63d679d844d6
46:02:28.251158 GUI: UIMediumEnumerator:  Items currently in usage: 590da495-7c65-4cb7-8c02-01d46a111bdc
46:02:28.251611 GUI: UIMediumEnumerator: Machine (or snapshot) event processed, ID = a048b75b-05e9-4046-bba5-28348177d106
46:02:28.307052 GUI: UIMediumEnumerator: Medium-enumeration finished!
46:02:31.943418 Console: Machine state changed to 'DeletingSnapshotPaused'
46:02:31.947040 Console: Machine state changed to 'Paused'

The guest was paused so I saved it and tried again to delete the snapshot and I got:

Code: Select all

Storage for the medium 'D:\VirtualMachines\Ubuntu\Snapshots/{6b4d92b6-39a6-4f37-87ce-ecb074124c74}.vdi' is being deleted.
Result Code: 
VBOX_E_INVALID_OBJECT_STATE (0x80BB0007)
Component: 
MediumWrap
Interface: 
IMedium {4afe423b-43e0-e9d0-82e8-ceb307940dda}

I closed the VirtualBox UI and reopened and now I was able to delete the snapshot.

EDIT: added more info

[mpack]

Well, it sounds to me like your snapshot problems are secondary symptoms of a stuck process. You should try to identify what the latter is, and whether it is something you are doing.

[klaus]

Yes, it seems that there's some medium state update issue. This is all secondary, though, until there's some information about the snapshot tree structure before the failed snapshot deletion. Without this information there won't be any progress (except by accident).

[klaus]

We found a bug with deleting snapshots (will take a while to fix and even longer to test). It's rejecting the deletion of a snapshot for no good reason, when it is done while a VM is running.

Without information how your snapshot tree looked like when deleting a snapshot and stating clearly which one was attempted to delete it's impossible to tell if this is anywhere near the issue you're seeing.