[linux-lvm] Snapshot question...

[Charles Marcus]

On 4/22/2008, dave at frop.net (dave at frop.net) wrote:
> The snapshot *looks like* a copy of the original volume for all 
> intents and purposes.  You can ignore the fact that it really only 
> saves the difference between the two volumes.  As far as you are 
> concerned, the snapshot is identical to the volume it was created 
> from at the time of the snapshot. 

and

> Your snapshot device is a *virtual* device. And if you do a cat
> /dev/vg/snapshot, you'll get 100GB worth of data which will be
> exactly the same as you would have gotten if you had done a cat
> /dev/vg/original at the time you did the snapshot.

<lightbulb>
Ahh... like say a link (soft? hard? not that it matters)...

Ok, makes sense now...

And yes, I figured the COW stuff was LVM voodoo-magic, so its good to 
know that I don't 'need to know'... :)
</lightbulb>

At least,  I hope I got it now...

Lastly...

Should the snapshot volume fill up, what happens to the original? I'm 
guessing that it would be protected from any kind of data loss?

Thanks for the hand-holding...

-- 

Best regards,

Charles