send/recv zvol, where does the data go?

[guermantes]

Hi,
When I send/recv a snapshot of a zvol (a VM) I see no files in the destination. Granted, this is a zvol and not a dataset, but where did zfs put my data? Did it create a dark hole I have no access to other than via zfs commands? WHITEDOT10TB is an off-site backup disk, can I be sure all necessary files are on it?

Code:

root@freenas:/mnt # zfs send TANK/nibelheim@manual-20181209 | zfs recv -F WHITEDOT10TB/nibelheim
root@freenas:/mnt/WHITEDOT10TB # zfs list -t snapshot
NAME                                                             USED  AVAIL  REFER  MOUNTPOINT
TANK/...<lots of snapshots...>
TANK/nibelheim@auto-20181209.0130-2w                             117M      -  6.84G  -
TANK/nibelheim@manual-20181209                                      0      -  6.42G  -
WHITEDOT10TB/foto@manual-20181208                                 96K      -   202G  -
WHITEDOT10TB/hibou@manual-20181209                                  0      -  20.5G  -
WHITEDOT10TB/home@manual-20181209                                   0      -   107G  -
WHITEDOT10TB/musica@manual-20181208                             23.0M      -  1.51T  -
WHITEDOT10TB/nibelheim@manual-20181209                              0      -  5.42G  -
freenas-boot/ROOT/default@2017-12-01-15:04:31                   2.41M      -   727M  -
freenas-boot/ROOT/default@2017-12-01-23:54:27                    632K      -   727M  -
root@freenas:/mnt/WHITEDOT10TB # ls -la
total 43
drwxr-xr-x   6 root        wheel         6 Dec  9 17:30 .
drwxr-xr-x   4 root        wheel       192 Dec  8 17:00 ..
drwxrwxr-x+ 10 peter       peter        12 Dec  4 09:49 foto
drwxrwxr-x+  8 peter       peter        13 Dec  4 09:24 hibou
drwxrwxr-x+  9 root        wheel        10 Oct 23 14:40 home
drwxrwxr-x+  4 linux_user  linux_user    5 Dec 11  2017 musica
root@freenas:/mnt/WHITEDOT10TB #

 

[guermantes]

Sorry. Perhaps I should have googled better. Is this the answer?
"Snapshots of zvols are not automatically displayed inside the file system hierarchy like file system snapshots are (because they can contain any other file system), but you can mount and access them at your chosen destination (again, depending on the content of the zvol). If mounting fails, you may try to first clone and then mount the clone"

 

[danb35]

When you replicate a zvol, it's stored as a zvol on the destination. You can see that it's there using zfs list; if you want to see its contents you'd need to mount whatever type of filesystem is contained on that zvol.