i want to clone a volume for a backup , when i do clone like a 2TB volume it is done in like seconds? is this a real clone or a clone built on a snapshot ? or there are something going on in the background?
It's actually both. Using code taken from snapshot the pointers to the pages are copied. If anything changes on the source volume, a pointer to the new page is created. The clone still points to the original data at the time the clone was created. So we don't have to actually copy 2TB to make/maintain a clone right away. So there's a lot of things that are going on in the background.
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I think you're asking "If I clone a volume, then delete the volume, will the clone still be there?" If so, then yes the clone will still be there. They are not interdependent.
Unlike clones, snapshots are dependent on the base volume, so if you delete a volume all its snapshot will also be deleted.
It's more complicated than that but it works like a snapshot. Because at the time of creation they are both identical. Just an object pointing to blocks on the disk. Making copies of the pointers is a quick process.
The space is allocated right away for the clone to insure there's enough space, unlike a snapshot which can be deleted if reserve is used up.
Thank you dwilliam for your quick reponse.
So basically, what I want to do is this
1) I have a LUN 2TBS called "Share Folders" and in use now i have 1.7 TB
2) So, i decide to make a new LUN clone of "Share Folders" and call "Shared Folders Clone" a quick process as you said.
3) Let's say, one day after, I got ramsoware on the original LUN "Share Folders" all data encripted
4) so basically, I am saved, because i have my lun "Shared Folders Clone" that points to pages where there is no encription on data.
am I right?
or should i have more than one day in order to have all data copied in a backgroud process from "Share Folders" to "Shared Folders Clone"
The actual process behind the scenes is proprietary, and a bit more complicated than that but the answer to your question is:
If I clone a volume is that data safe should something happens to the volume it came from? Yes, the clone is safe. As a clone (assuming not mounted to a server that's also infected) not a mirror it's data is intact as of the time it was created.
Changes to the original volume aren't carried over to the clone.
The only way to modify a clone is to connect to it and write data like any other volume.
A clone is a point-in-time copy that does not expire like a snapshot.
Does that explain it better?