[linux-lvm] exposing snapshot block device

[Zdenek Kabelac]

Dne 22. 10. 19 v 17:29 Dalebjörk, Tomas napsal(a):
> Thanks for feedback,
> 
> But, it would be better if the cow device could be recreated in a faster way, 
> mentioning that all blocks are present on an external device, so that the LV 
> volume can be restored much quicker using "lvconvert --merge" command.
> 
> That would be super cool!
> 
> Imagine backing up multi terrabyte sized volumes in minutes to external 
> destinations, and restoring the data in seconds using instant recovery by 
> re-creating or emulating the cow device, and associating all blocks to an 
> external device?
> 

Hi

I do not want to break your imagination here, but that is exactly the thing 
you can do with thin provisioning and thin_delta tool.

You just work with LV, take snapshot1, take snapshot2,
send delta between  s1 -> s2  to remove machine,
remove s1, take s3, send delta  s2 -> s3...

It's just not automated by lvm2 ATM...

Using this with old snapshot would be insanely inefficient...

Regards

Zdenek