[linux-lvm] Snapshots of snapshots are not supported yet

markw at mohawksoft.com markw at mohawksoft.com
Wed Jul 10 20:12:32 UTC 2013

> Dne 10.7.2013 16:45, markw at mohawksoft.com napsal(a):

> As I said -  btrfs has some kind of functionality you are looking for,
> Or you may start to help with lvm project...
> (Or thin-provisioning tools in this case)
> Zdenek

That link you sent was good, I am looking in to it, it may provide a large
amount of help.

One last thing.... :-)

Now imagine this:

create disk0

Activity on disk0

Take a snapshot
disk0 -> disk0_snap0

Activity on disk0

take a snapshot
disk0 -> disk0_snap1

(We will now use the differential between snap1 and snap0 to represent
what needs to be backed up from snap1)

This leaves us with something that looks like this:

disk0 --> disk0_snap0
       -> disk0_snap1

Will we need to remap the parentage of disk0_snap0 so it looks something
like this?

disk0 -> disk0_snap1 -> disk0_snap0
(Is this possible with dmsetup?)

Or could we have many (order of hundreds or thousands) of snaps directly
on disk0 and not impact performance?

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