Best approach to handle jail while experimenting.

[passatiji]

Can someone help me understand how to use the tools of Truenas for the following scenario?
I would like to setup a jail to install FEMP server and Joomla CMS for my own learning and have a safety cushion in case I do something wrong. So I was thinking I could make manual snapshots before major changes and hopefully be able to rollback if that step fails. Before I end up with disaster recovery (not that it's production server but still) I decided to play with snapshots and rollbacks but it didn't seem to work. Here is what I did:

• System version: TrueNAS-12.0-U7
• Created clone jail Release 12.3
• GUI: Storage -> Snapshots (there was already a snapshot with the jail name)
• Snapshot Add (Dataset: Storage/iocage/jails/FEMPserver) the rest default
• GUI: Jails ->FEMPserver -> Shell -> wget installation.tar.gz
• GUI: Storage -> Snapshots -> (manual snapshot) -> Rollback -> Confirm -> Rollback
• GUI: Jails ->FEMPserver -> Shell -> ls -> installation.tar.gz (still there!?)

I was expecting the state of the jail to be back to the point of creation but in my case freshly downloaded file was still there
Obviously, I am missing something (most dialogues were left by default) and don't intuitively see where I am making the mistake.
My question is: How can I use the advantage of ZFS snapshot to be able roll back a step (or a couple steps) of jail modifications?
Thank you.

 

[Patrick M. Hausen]

You need to roll back all the datasets of your jail individually. There is no such thing as a recursive rollback in ZFS. There are recursive snapshots, though, and you should check if you enabled that when you created the snapshot.

Storage/iocage/jails/FEMPserver just contains the jail's metadata. All the jail installation proper (unless you changed that by mounts or other measures) is in Storage/iocage/jails/FEMPserver/root ...

 

[passatiji]

You need to roll back all the datasets of your jail individually. There is no such thing as a recursive rollback in ZFS. There are recursive snapshots, though, and you should check if you enabled that when you created the snapshot.

Storage/iocage/jails/FEMPserver just contains the jail's metadata. All the jail installation proper (unless you changed that by mounts or other measures) is in Storage/iocage/jails/FEMPserver/root ...

Thank you for the quick response.
First mistake that I made - didn't enable recursive option. I will play with that shortly.
Second remark is what I think is causing my frustration - I'm rolling back wrong folder dataset (not root).

 

[passatiji]

Storage/iocage/jails/FEMPserver just contains the jail's metadata. All the jail installation proper (unless you changed that by mounts or other measures) is in Storage/iocage/jails/FEMPserver/root ...

You were absolutely correct. Rolling back "root" dataset works exactly as expected.
Thank you!