Which macOS folders are safe to put on ZFS?

All your general support questions for OpenZFS on OS X.

Which macOS folders are safe to put on ZFS?

Postby pat » Thu May 06, 2021 9:53 pm

Boot on ZFS seems to be a no-go right now, at least on Catalina on my 2015 MacBook Pro. That leads me to wonder, how much of the macOS system can I put on ZFS, assuming that I maintain the macOS install on APFS? In particular, I am wondering how it works with upgrades.

Here are the root folders, and some hunches:

- /Applications - Maybe? I would love to ZFS this folder. My main concern is regarding macOS updates. If macOS updates e.g. Terminal.app when the ZFS pool isn't mounted, then the next time I mount /Applications I won't actually be getting the macOS updated version.
- /Library - no idea. Possibly the same as /Applications. If macOS reads / writes from it before mounting ZFS, that could cause problems.
- /System - I assume that at least a big chunk of this can't be moved to ZFS.
- /Users - certainly. It's probably a good idea to create an `admin` user on the APFS volume so there's at least one login that isn't dependent on ZFS

Have other people moved /Applications and /Library on to ZFS (and kept the APFS macOS install)? If so, have you run into any problems - and how does it work with Software Update?
pat
 
Posts: 12
Joined: Mon May 03, 2021 11:58 pm

Re: Which macOS folders are safe to put on ZFS?

Postby soongrazer » Thu May 13, 2021 4:43 pm

I keep using macOS Catalina on my MacBook Pro. I have once used ZFS for /Applications. It works okay with the exception of the Dock. The icons in the Dock behaves unexpectedly when it was on ZFS though I didn't try with com.apple.mimic on.

/Applications only stores the applications you install with the exception of Safari. The system applications are in /System/Applications. You can see the list of applications that actually exist in /Applications in Terminal. For me, Safari didn't work by just restoring the Safari.app to a ZFS file system. I had to install a beta version and wait for an update in System Preferences.

I have installed macOS Catalina Supplemental Updates and it worked well.

Haven't tried /Library and /System.

/Users works but iCloud Drive doesn't work. There is root user you can enable. The home folder for root user is /var/root.
soongrazer
 
Posts: 5
Joined: Sun Dec 06, 2020 5:58 pm

Re: Which macOS folders are safe to put on ZFS?

Postby pat » Wed May 19, 2021 9:56 pm

Hrm interesting. As mentioned in my other thread, I will be sticking with ZFS only for my personal data. It would be great to use it for more system stuff as well, but it seems like there are too many potential gotchas. And ultimately my personal data is what can benefit most from ZFS. Thanks again.
pat
 
Posts: 12
Joined: Mon May 03, 2021 11:58 pm


Return to General Help

Who is online

Users browsing this forum: No registered users and 3 guests