How do I safely delete snapshots?

[hilarious]

I've had 2 VDI files on my F: drive. Then Linux update killed one of my VMs and after I reinstalled it I made snapshots of both VMs so I can quickly restore them if it ever happens again. I saved them on my small SSD.

As I just found out those snapshots aren't really static and in fact have been my primary usage files. They've grown a lot and those VDIs on F: drive haven't been touched in months.

What should I do to keep my current states and move most recent VDIs to F:?

[scottgus1]

Best thing to do is make a full clone of the snapshotted vdi's (See CloneVDI). Use the cloned drive in your guest instead. Don't delete anything until you have your guest running perfectly on the cloned unsnapshotted vdi.

Snapshots make a guest more delicate and do not work as backups. They should only be used on guests you're experimenting with and with data you wouldn't mind losing. (The forums are replete with users destroying their important data because they did something wrong with a snapshot.)

Better way to restore a guest is to back it up safely. See this tutorial Moving a VM and re-interpret it as "Backing Up a VM".

[mpack]

Best thing to do is make a full clone of the snapshotted vdi's (See CloneVDI). Use the cloned drive in your guest instead. Don't delete anything until you have your guest running perfectly on the cloned unsnapshotted vdi.

Far be it from me to dissuade people from using CloneVDI, but in fact nowadays I'd recommend that you use the inbuilt VBox cloning function (right click, Clone) when cloning a VM. The difference is that the VirtualBox feature clones the VM, while CloneVDI only clones the selected media file. Also the VBox feature gives you fewer choices as to which snapshot state to clone, hence less room for error.

Make sure you choose "Current state only" when you are asked what to clone - this is the option that ensures that the snapshot structure is not copied as well.

Oh, and in future: don't confuse snapshots with backups. They aren't. They are more akin to restore points. By their very nature they freeze the current state and then have to record every deviation from that state into the future. IMHO it's much more clear cut to make a proper backup of your VM (to secondary meda) when necessary.

Final note: I detect the newbies common fixation with VDI files. The VDI is a disk, not the whole VM, and the other files while smaller can be just as important. Always move the entire VM folder as a unit, do not move the VDI. Howto: Move a VM.

[hilarious]

Thanks guys. In the end turned out that clicking delete on the snapshot actually merges the VDIs so it's exactly what I needed. Instead of a 14 Gb on C and 10 on F I got a single 22Gb file on F: now.

Merry Christmas

[mpack]

Thanks guys. In the end turned out that clicking delete on the snapshot actually merges the VDIs so it's exactly what I needed.

Hmm. Except that you asked for the safest way to delete a snapshot, not the easiest. Now that it has worked you are fine, but had it failed (e.g. due to some kind of disk error) you could have lost the VM.

[scottgus1]

The difference is that the VirtualBox feature clones the VM, while CloneVDI only clones the selected media file.

Mpack, Doesn't cloning the whole guest change the "motherboard" UUID presented to the guest? I have a vague recollection that re-activation issues or grub loader issues might happen?

[mpack]

Yes, that's quite correct, but the OP was going to have to create a new VM anyway, if the intention was to make sure it was working prior to making any big changes to the original VM. The possible issues this could cause would just have to be dealt with - none are as catastrophic as a snapshot delete that goes wrong.