Purpose of .system hidden dataset

[dobler]

The primary pool on a FreeNAS system (not the rpool), creates an invisible .system dataset. I would assume this is to allow the base pool to be stored on an embedded solution like a flash drive.

My question is how to deal with this filesystem. It makes it slightly difficult to deal with zfs replication because it recursively backs up all these .system datasets.

Ideally, I would like to store this on a pool of my choosing so that I can avoid it altogether. Is this possible?
Alternatively, is there a way to avoid hidden datasets on recursive zfs send?

Also, is the data in this filesystem important? Can it be deleted without causing issues?

 

[gpsguy]

Assuming you are using FreeNAS 9.3, see section 5.6 of the manual.

At a minimum "System → System Dataset, shown in Figure 5.6a, is used to select the pool which will contain the persistent system dataset. The system dataset stores debugging core files and Samba4 metadata such as the user/group cache and share level permissions."

You can change the specify the pool. If you change it now, it'll migrate the data to the new location.

 

[danb35]

Ideally, I would like to store this on a pool of my choosing

Simple--choose a different pool as gpsguy has indicated.

so that I can avoid it altogether.

Impossible--the contents need to be stored and need to be persistent.

Alternatively, is there a way to avoid hidden datasets on recursive zfs send?

Rather than replicating your entire pool, replicate the datasets that are of interest to you.

Also, is the data in this filesystem important? Can it be deleted without causing issues?

Yes, it is, and no, it can't.

 

[dobler]

Thank you for the clarification.

 

[daverino]

Hi,

I have a related question. I want to change from a 3 disk raidz to a 4 disk raidz. Since my system cannot accommodate 7 disks, I made a recursive snapshot of my zpool "tank" to an external disk and received it on the new zpool "newtank/tank". I now have two .system directories: /newtank/.system and /newtank/tank/.system. How do I deal with that?
I use Freenas 9.2.1.8-RELEASE-x64.

Thanks in advance

David

 

[cyberjock]

From my perspective it seems straightforward. Delete the old one (/newtank/tank/.system). Is there a reason you don't want to do that or you just looking to validate that deleting it is okay?

 

[daverino]

From my perspective it seems straightforward. Delete the old one (/newtank/tank/.system).

I agree with you. That's what I normally would do, but since danb35 stated the importance of the .system dataset I am wondering what was probably lost, when FreeNAS had to create the new /newtank/.system. Also if I might have to merge the two.

Is there a reason you don't want to do that or you just looking to validate that deleting it is okay?

And yes, I just want to validate that deleting it is okay. Everything seems to work nicely.