Live Snapshot and disk size

[dutangp]

Hello Everybody,

I'm currently using the last version of Proxmox cause I'm interested about the new feature live snapshot.

I have doubts about how these live snapshots works about the size of the virtual disk that I find in ./images/###.

Basically I set a virtual disk at 30Go for an ubuntu virtual machine, with a machine with around 10 snapshots the real size of the virtual disk (qcow2) is around 100Go. I really don't understand how all the snapshots are saved in the virtual disk.

thanks for you help

best,

 

[dietmar]

see http://git.qemu.org/?p=qemu.git;a=b...559d8867c3afaf2c2c9d6ebd684e1f810eab6;hb=HEAD

 

[dutangp]

Hello Dietmar,

I read the document but I'm not sure to understand why I have a big difference between what I declared first for the virtual disk (30Go) and after few snapshots (around 10) qcow2 is around 100Go.

It's a huge difference!!!

Thanks for your help

best,

 

[spirit]

Hello Dietmar,

I read the document but I'm not sure to understand why I have a big difference between what I declared first for the virtual disk (30Go) and after few snapshots (around 10) qcow2 is around 100Go.

It's a huge difference!!!

Thanks for your help

best,

Hi,
when you make a snapshot, it take 0 disc space at the creation time.
Now, all new writes after the snapshot take space. So you can eventually have a snasphot space equal to disk space if you rewrite the full disk.

 

[dutangp]

ok I got it.

So that's means if I make several snapshots with different data inside and I delete a specific snapshot, basically the qcow2 size have to be less right?

cause mine stay in the same size, it's really strange

best,

 

[spirit]

ok I got it.

So that's means if I make several snapshots with different data inside and I delete a specific snapshot, basically the qcow2 size have to be less right?

cause mine stay in the same size, it's really strange

best,

mmm, not sure about it, maybe only meta-datas are deleted when you delete a snapshot. (it's easy to check, does it take seconds or minutes to delete the snasphots ?).
But If you write new datas, it should overwrites old datas.