Kali snapshot fail...

[FXben]

Hello all,

I would like to say that I'm new here and new to Linux so please bear with me.

Anyway, I have a fresh installation of Ubuntu that is fully updated and with a fresh install of Virtualbox with a Kali installation that is again fully updated and working. However when I try to make a snapshot Virtualbox crashes on 96% with this error code: Result Code: NS_ERROR_ABORT (0x80004004). I have tried searching for a solution but have come up with nothing useful. I remember reading something a few days ago that snapshots aren't necessarily the best way to revert to a previous state but cant remember exactly what was said as to a different option. Would that be the clones option possibly? Is there anyone who can help me please? If anymore info is needed please ask.

Thank you

[mpack]

Does it really crash? Because that looks like it didn't crash, it just gave you an error, which you haven't reported completely. Do you understand the difference between an error and a crash?

At a guess, I'd say the operation failed because you ran out of host disk space, so that's an obvious thing to check and report.

Btw, snapshots can be used to revert to a previous guest state (though I wouldn't). What they can't do is substitute for host backups. It's like restore points in Windows: totally useless if your PC fails.

[FXben]

Yes I do know the difference between an error and a crash.

I'm assuming it is a crash because the vbox manager in the snapshots tab lists no snapshots and also when I try to create a snapshot it fails between 90 - 96% with a crash. In other words Kali is no longer running because it Crashed and its status shows Aborted... That doesn't seem normal, I watched a Youtube tut and the guy's Kali never shutdown it went grey and then back to a normal state. As for the host disk space its not that, I have plenty...trust me.

I have also tried making a snapshot without Kali running. What do you mean not reported properly? I did report it every time this happened.

EDIT: I just tried to make a snapshot again but this time I had no option for reporting it... maybe that happened last time also? but I tried 3 or 4 times before that and reported the error/crash w/e...

EDIT 2: I just looked in the Virtualbox VMs folder and found the snapshots folder and there are what looks like Kali snapshots in there so I'm a little confused with the conflicting results of the snapshot process.

[socratis]

installation of Ubuntu that is fully updated and with a fresh install of Virtualbox

Where did you get the VirtualBox from? Is it from the Ubuntu repository or from the Downloads section of VirtualBox (https://www.virtualbox.org/wiki/Downloads)?

Are you trying to take a snapshot while the Kali VM is running?
Why do you need to take a snapshot at that state?

About the Snapshots folder, that maybe incomplete snapshots, if as you say, you get an error in the process. I'm not sure I would trust them.

[FXben]

I got Virtualbox from the official site that you mentioned. I have tried to take a snapshot while Kali is running and while it isn't.

You asked why I want to take a snapshot, well...

I've been a fairly 'pro' PC user user for years when it comes to windows at least anyway. I just want to make it clear that I'm not stupid or a child. I'm a gamer mostly, I ran a gaming clan for quite a few years but I do lots of other things as well such as 3D modelling, using Photoshop, and I generally like to learn new and interesting things. I've thought about giving Linux a try for years but only this week have I jumped in. I'm dual booting Windows 10 and Ubuntu so everything is new to me at the minute. I'm running through tutorials on anything and everything Linux, pro-actively learning. I made some errors whilst messing around with Kali and I ended up having to delete it and starting over so I figured after updating it then I would take a snapshot for easy retrieval if I mess up again. That is what they are there for no? The updates take quite a while and I thought this would be a quick way to get back to where I was at.

Sorry for the essay, I just thought a little background might help with understanding my issue and where I'm at as to someone being able to explain things to me, and yeah I kinda figured those snapshots were useless as I'm definitely getting a crash during the process.

Thanks for the reply's too, much appreciated...

[socratis]

OK, fair enough, but I wouldn't recommend two things:
a) Live snapshots.
b) Pilling up, tree snapshots.

Read the following nice explanation about differencing disks and snapshots (which are based on the concept of differencing disks) and you'll pretty easily figure out why they can be really bad sometimes, if you don't understand the way they work.

When a virtual disk is first created for a new virtual machine, it is considered as the base disk for the guest - data for the guest is read from and written to that disk image.

The differencing disk records changes sector-by-sector to the whole disk image, not changes to any file in the disk. VirtualBox does not know what file system is employed on the disk image and therefore can not access any individual file of/on the disk image; only the guest OS is aware of that information.

First SnapShot creates a differencing disk for read/write access while the base disk becomes read-only - as the guest modifies its data, the data is written to the differencing disk and the base disk is untouched.

Second SnapShot creates another, new, differencing disk for read/write access while the first differencing disk becomes read-only along with the base disk.

Subsequent SnapShots create additional differencing disks, with the preceding differencing disk joining the hierarchy (pecking order/chain) of read-only disks.

Keep in mind that access to/from the virtual disks is sector-by-sector, not file-by-file.

When the guest requests that a sector be read, the latest SnapShot is read first. If the sector is not found there (Sector-Not-Found is returned), the next SnapShot in the chain (youngest to oldest), until the base virtual disk is reached. Then the sector on/in the base virtual disk is either read or Sector-Not-Found is returned.

The way I use them is as follows:
• Install the basic OS. Snapshot.
• Install the updates. New Snapshot, merge Base with the previous Snapshot.
• Install software. New Snapshot, merge the Base with the previous Snapshot.
• Test, test, test. After I'm done I always revert to the last Snapshot.

That way I have a fresh system with one and just one, minimum snapshot. But things could go bad, like everything.

Some people prefer a full backup of the VM folder, yet others prefer to do their testing on a clone VM and if successful then apply the test to the original. These last two choices have the least potential to go belly-up, but they're more time-consuming. It's your choice.

[FXben]

Ahh lol, OK thanks.

As you can probably tell I'm still in a windows mind set. Cheers for the info though, appreciated.

[socratis]

I knew that you'd see the light. The fragility of the snapshots is legendary, mainly due to the fact that 1) people don't realize it's NOT a backup and 2) they don't realize that it's a chain; if you delete a middle one the whole future ones are useless.

Still that does not address your original issue. You should be able to take a snapshot, even a live one. I've done it in a test machine, by accident (fat fingers for wrong shortcut). I'm not sure if the action of creating a snapshot creates a log, that's why this is hard to debug.

Shooting in the dark here: Is there a chance that you can completely uninstall and re-install VirtualBox in the rare case that something has gone wrong during the installation? And install a second VM?

[FXben]

Sorry for the late reply,

Funny you saying that... I already tried that, thinking like you that something might have gone wrong with the installation however I'm getting the exact same results. So like you say I'm not really fixing the problem I have which is frustrating to say the least (I hate having unfinished business). I'm not sure that I'll use the feature though so maybe i'll come back to it again if the need arises in the future. Seriously though I really appreciate the help and advice, you sir are a gent...

[Perryg]

Something that is missing here that would help to explain your issue is the guest log file ( as an attachment ). It could show why you are having this issue. Personally other than testing I don't use snap shots but it works for me and has for a long time.

I would also like to see the results of df -h from the host terminal as well.