Intended method to automatically mount root on ZFS

[m0nKeY]

Thank you for you answer and the information.

@dalto

There are literally multiple ways to do it. All are rational. zfs in general isn’t a thing that only works a single way. It is intended to be flexible and used in different ways. Different people have different preferences.

That being said, the method described the arch wiki using the zfs-mount.service is definitely more common and more simple.

I understand that, there is now “wrong” or “right”. But there has to be reasons to choose one or another solution. That is, what I’m trying to understand. E.g. my configuration, from the OpenZFS Wiki “Root on ZFS” for Arch, is using the fstab method, to control the order folders are mounted more precisely:

At boot, datasets on rpool are mounted with /etc/fstab , which can control the mounting process more precisely than zfs-mount.service .

So what are the pros and cons using other method?

@dalto

I just looked at the wiki you referenced. It looks like it is setting canmount=noauto on all datasets with mountpoints then mounting them manually by zfs using the zfsutils mount option in /etc/fstab. That is yet another valid way to do it.

For the dataset that isn’t working for you, did you set canmount=noauto and set the mountpoint properly

I don’t really think that is the “official method”. I think that the author’s preference. If a descriptive howto like that described all the options, it would be very long and confusing.

As far as I understand it, it is using the canmount=noauto property only for the root dataset ‘rpool/manjaro/ROOT/default’. I’m not using a boot pool, that did not work out for me.

So for me the scheme is:

1. Every virtual dataset gets the canmount=off property set, because it just used for organisation and inheriting properties to child datasets.
2. The datasets for /usr, /var and /var/lib are set to ‘canmount=off’. This is mentioned in nearly any howto I found, even though I don’t know the actual reason.
3. All other datasets, which are actually mounted have the `canmount=on’ property set.

The dataset, which is not working for me, is discussed in another thread
(Manjaro not booting, because it fails to automount ZFS dataset) as I wanted to split this topics. But its canmount property is set to on.

@dalto

That is how fstab works on a system with systemd. It does that for everything in /etc/fstab with any filesystem.

Thx again, that is something that I did not know.