Fred did you ever get this figured out? I asked the same question 10 days ago and its "crickets" - your post has had crickets for 6 months so I suspect I may have better luck just asking if you got this resolved?
Ok I figured it out so I might as well add it as a response here in case someone searches. The good news is that you can add mounts onto the Asigra tool without needing any special shell commands. I have my jails in a much smaller pool than my main storage pools and I wanted to keep Asigra in the jail pool and the backup in the main storage pool. To do this requires three steps and assumes Asigra is already up and running in the jail pool. By default Asigra sets up storage is in the same place as the actual jail is running in : zdata/root is the directory path under the root shell...
What needs to be done:
1. Create and/or identify the dataset that will hold the data and which you will mount to the jail
In my case: Dataset named DSBackup under a Pool Named Tank
I chose to put the mount in the same folder that the tool uses by default to create its storage (zdata). I am not sure it needs to be there but why not and it avoids having to deal with other possible quirks with the tool. I may add that you arent limited to one mount and can add multiple different mounts from different datasets.
3. Restart the jail. The last step is to configure the jail from within the Asigra DS-Operator management tool (click Manage and bring window up from thre or go to the admin portal - we need a GUI and not Java but thats a different wish). If you go to storage --> extensible Storage Locations you will notice you can hit ADD button. You should be able to see the mounts you added in step 2, configure the size and hit OK. Yep you should BUT you will get an error message indicating you cant add paths from the same location. By default Asigra WILL NOT let you specify multiple paths from the same place. Turns out you have to override that setting to allow it...
3a: To allow multiple folder paths from the same volume (Asigra sees any mounts you have done as coming from the same volume) you have to first go to
Setup --> Advanced Configuration and find the MultiStorage Parameter and set it to 1
While Im add it I also noticed a cool feature: - when you add a storage location you have the option of adding a storage group and storage volume as options. Ive not played with the storage volume BUT the storage group allows you to tag each mount you have done. When you set up backups you can actually specify WHICH of the tags you want the backup to go to. I think if you leave the group as default it will span the multiple storage locations and see it all as one big storage area.
To better explain:
I set up two mounts to two different datasets.... one is 1TB for my critical bakup and the other in a differnt pool is for my kids junk on less reliable drives. If I had mounted both and left them in the default storage group both datasets would have been seen by ASigra as one big storage area. By tagging each mount as a different storage group Im able to tell the tool to backup my critical data to one group and the kids data to the other group.
In any case Im sure you figured it out since its been 6 months since you posted but Im hoping this will save some time for others.... the two key items that go me going were the fact ASigra stores the stuff under the zdata by default and that you had to go overridge the multistorage flag!