SOLVED I need some help with Jail Storage working unexpectedly

[hansmuff]

System: FreeNAS 9.3 STABLE/current patches
Hardware: X10SL7-F, Xeon 1231v3, 32GB ECC, 3x 4TB drives raidz. Booting from 2x USB in raidz config.

I have a number of jails that run plugins like Plex, Crashplan etc.
Those were all installed the 'standard' way of the plugin manager (so they are 'pluginjail' types.)
I'm not using VMIMAGE on any of my jails.

To most of them, I have storage mappings defined and they all work as I expect.
Recently, I wanted to change a mapping in my crashplan setup:

Host: /mnt/den/aslan/music
Jail: /den/aslan/music

That worked, and crashplan backed up all the directories and sub-directories in there.

Now I wanted to back up more than just my music. So here's what I did:
1. Stop crashplan plugin
2. Remove /mnt/den/aslan/music mapping in 'Jails -> Storage'
3. jexec tcsh to the crashplan jail, rm -rf /den/aslan
4. Define new mapping:

Host: /mnt/den/aslan
Jail: /den/aslan

5. Restart jail
6. Restart crashplan
7. jexec tcsh to crashplan jail

When browsing the new /den/aslan mapping, I noticed the following:
On the host, the structure is
/mnt/den/aslan/downloads
/mnt/den/aslan/series
/mnt/den/aslan/music
/mnt/den/aslan/movies

Now, in the jail, I see that exact sub-tree. BUT, only the 'music' subdirectory shows data in it, the rest are all completely empty. The host has about 1TB of files strewn all over those directories.

I re-did the above steps and added a server re-boot in there for good measure, but no dice.

It is almost as if the jail remembered that it used to be able to see the /den/aslan/music files (but no others in /den/aslan) and worked exactly like so. Even though that mapping was completely removed.

I had to go and map each one of those sub-directories, one by one, with their own mapping in 'Jails -> Storage' and now I can see all the files.

So that makes me suspicious. It doesn't seem to be a permissions problem or the 2nd approach wouldn't work. Clearly, also, those files are there.

Why did the first approach of mapping just the top directory and having all its sub-directories available?
I have that exact thing going on with other directories in the same jail! There's a /mnt/den/simba that has tons of files and subdirectories, and those all show up in the jail with just one Jail Storage mapping.

Any help greatly appreciated. I feel I'm missing a piece of knowledge here.

 

[Robert Trevellyan]

If the subfolders of/mnt/den/aslan are individual datasets, they won't show up in the jail. Each dataset has to be mounted individually.

 

[hansmuff]

... and that explains it. I had no clue, thank you so much for clearing that up for me. They are separate datasets.