Snapshot and snap restore of a nested dataset

[DataMover]

Please help me to clearly understand:

Say, I have a ZFS volume "my-zvol", a dataset under that volume "my-toplevel-ds" and another dataset "my-2ndleve-ds" nested under the first, giving me something like this:

my-zvol/
----my-toplevel-ds/
----my-2ndlevel-ds/

Now I snapshot only my-2ndlevel-ds and replicate it to another ZFS volume on different, external disks either on the same host or another. Snapshots and replication is created and done through the FreeNAS GUI, recurring and incremental.

Now assume, that my FreeNAS system gets lost in... say a fire, but I will still have the external disks. I buy new hardware, install FreeNAS and.....:

Will I be able to restore my-2ndlevel-ds and all it's data (assuming all replication up to the fire has been successful) from the backup? Will I have to rebuild the structure above it (my-zvol and my-toplevel-ds) manually before I restore or will it be created automatically by restoring (without data of course, because I haven't snapshotted any content of zvol or my-toplebvel-ds)?

Kind regards
DataMover

 

[fracai]

Snapshots can be recursive in that a single snapshot command can create snapshots for any nested datasets, but the "parent" snapshot will not contain any data from the "child". You'd still need to replicate the child snapshot.