[Solved] Using Snapshot to backup incremental

[Mariano0]

Hi,

I need to make weekly backup of the contents of the virtual disk to an external USB disk.

I would like to know if it will work to copy the complete virtual disk to the external disk (USB) and configure the location of the snapshot to the external disk (USB). In such a way that when I finish using the machine I create a snapshot; equivalent to incremental backup?

This is to reduce the size of the copies and not have to copy the entire virtual disk.

Translated by google translator.

Thanks.

[socratis]

Snapshots are not backups!

If you want an outside-the-VM backup, you have to copy the whole VM folder: Moving a VM (just the copying part).

If you want an inside-the-VM backup, you need to find a backup client. Think of the VM as an independent computer.

[Mariano0]

Thanks for information.

Of course, I understand that it is not for backup. But I understand that it is used to return to the state at the time it was captured. So it occurs to me that I could use it as a backup to not use other third-party software and not have to copy the entire VDI file to the external disk. I suppose that the snapshot works together with the complete VDI, that is, it loads the complete VDI and then the snapshot with the modifications.

I think it would be a very simple way to use it as a backup and we would even have different versions of the files.

Am I right or is there something I still do not understand?

[socratis]

we would even have different versions of the files.

Not the files. The hard disk sectors. Huge difference!
You're thinking in terms of backups. They're not backups. They're a chain of differential patches to the main VDI. If one patch is not there, the whole thing doesn't work. Read viewtopic.php?f=35&t=84332 although I still need to put some work on it and clarify a few things...

[Mariano0]

Excellent! I would like to review to see if I understood correctly.

The VDI file created from the first time becomes the base file. When you create the instantaneous 1, a copy of the modified sectors is created. Running the machine again creates a disk state, loading the previous two modifications of the sectors and so on.

So the last snapshot, you will need all the previous ones to be able to load all the sectors with their corresponding modifications. If a copy is missing, sectors will be missing and the last state can not be loaded.

[socratis]

Yeah, something like that... with minor (but important) corrections:

When you create the instantaneous 1, a copy of the modified sectors is created.

When you create the 1st snapshot, the modified sectors are kept/recorded in the new snapshot. (it's not a copy).

If a copy is missing, sectors will be missing and the last state can not be loaded.

If a snapshot (it's not a copy) is missing, sectors will be missing and any state after the missing snapshot can not be loaded.

[Mariano0]

Perfect! I get it. Now I understand why I should use a backup client.

Thank you so much for everything.