[ZFS] Send unencrypted dataset to encrypted pool

I recently added some disks to my TrueNAS server and created a new encrypted pool named data2 on it. My old pool data was created years ago, before the zfs encryption feature was released, so it is an unencrypted pool. Now I wanted to move a dataset, i.e. photos, to my new pool data2. I tried to archive this via TrueNAS Gui using the Replication Task, but always got errors that it’s not possible to send unancrypted data to an encrypted pool.

On Reddit I found a thread with a solution using the parameter -x encryption.

Because I prefer keeping all my snapshots when moving a dataset, I first send my oldest snapshot.

zfs send -v data/photos@manual-01-05-2019 | zfs recv -x encryption data2/photos

In the next step I created a new snapshot and did an incremental send with the paramter -I (send incremental snapshots).

zfs send -v -I data/photos@manual-01-05-2019 data/photos@manual-01-10-2020 | zfs recv -F -x encryption data2/photos

Compare the folders with:

diff -qr /mnt/data/photos /mnt/data2/photos
#or in background
diff -qr /mnt/data/photos /mnt/data2/photos >> diff.output & disown
#check if process finished with "ps"
less diff.output

Check if all Snapshots were replicated with:

zfs list -t snapshot | grep data2/photos

After that I just changed the path for my NFS photo share and did a sudo mount -a on the clients. Now the whole dataset is moved and encrypted.

[ZFS] import pool: “cannot mount ‘/’: directory is not empty”

$ sudo zpool list
NAME             SIZE  ALLOC   FREE  CKPOINT  EXPANDSZ   FRAG    CAP  DEDUP    HEALTH  ALTROOT
data            10,9T  10,3T   577G        -         -    46%    94%  1.00x    ONLINE  -
externalBackup  5,44T  4,19T  1,25T        -         -     0%    77%  1.00x    ONLINE  -
rpool            111G  27,4G  83,6G        -         -    40%    24%  1.00x    ONLINE  -

$ sudo zpool import externalBackup
cannot mount '/': directory is not empty

$ sudo zfs set mountpoint=/externalBackup externalBackup

$ sudo zfs get mountpoint externalBackup
NAME            PROPERTY    VALUE                SOURCE
externalBackup  mountpoint  /externalBackup  local

$ sudo zfs get mounted externalBackup
NAME            PROPERTY  VALUE    SOURCE
externalBackup  mounted   no       -

$ sudo zfs mount externalBackup

$ sudo zfs get mounted externalBackup
NAME            PROPERTY  VALUE    SOURCE
externalBackup  mounted   yes      -