Question re: ZFS

[Alex Smith (K4RNT)]

Hey everyone,

I'm running Xubuntu 22.04.3 Jammy, and have some questions for the ZFS experts of the list.

I have several ZFS pools in my system, and have a ZFS pool for a single NVME SSD, which I have set up for my home directories. The /home directory was originally under /, and I have successfully sent the data over to the new pool, but I am having difficulty with the old filesystem, which is still mounted for /home/alex, and it reports that it's busy.

Can I set up the old filesystem to not be mounted automatically on future boots? Do I have to destroy the filesystem, or can I keep the old data. I have snapshots as well.

Here are my filesystems.

homepool                                           441G   458G       24K  /homepool
homepool/USERDATA                                 59.5G   458G       24K  /homepool/USERDATA
homepool/USERDATA/alex_b7ww6i                     59.5G   458G     59.5G  /home/alex

homepool/home                                      382G   458G      382G  /home

rpool/USERDATA                                    45.7G  83.8G       96K  /

rpool/USERDATA/alex_b7ww6i                        45.4G  83.8G     45.4G  /home/alex
rpool/USERDATA/root_b7ww6i                         383M  83.8G      383M  /root

alex@wenatchee:~$ sudo zfs unmount rpool/USERDATA/alex_b7ww6i
cannot unmount '/home/alex': pool or dataset is busy

 

My problem is that there are two filesystems with the same mountpoint. I don't know how to resolve this.

Thanks for all the help in advance!

" 'With the first link, the chain is forged. The first speech censured, the first thought forbidden, the first freedom denied, chains us all irrevocably.' Those words were uttered by Judge Aaron Satie as wisdom and warning... The first time any man's freedom is trodden on, we’re all damaged." - Jean-Luc Picard, quoting Judge Aaron Satie, Star Trek: TNG episode "The Drumhead"

- Alex Smith (K4RNT)

- Lacey, Washington (Olympia, WA metropolitan area)

[Tilghman Lesher]

Your current PWD is your home directory, which is why you can't unmount it.

Change your working directory to '/', and try again.

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[Kent Perrier]

That won't work if he is logged in as himself. Log in as root and do the magic to /etc/fstab. Or do the magic to /etc/fstab, reboot and hope it's right! :)

Kent

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[Michael L]

Can I ask what you mean by "do the magic" to /etc/fstab?

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[Kent Perrier]

Going back and reading your OP, you need to not mount your user's home directory over /root. (root should certainly have it's own home directory and share your regular user's home directory.) Comment that out of /etc/fstab, reboot, log in as root and your home directory should not be used, so you can unmount it (I assume that both  rpool/USERDATA/alex_b7ww6i and  homepool/USERDATA/alex_b7ww6i  are not mounted to /home/alex at the same time as shown.) Now you can mount homepool (assuming that is the new one) up to your /home/alex mount point. The magic is doing these edits to /etc/fstab without being able to unmount the file systems and test outside of rebooting. If it's wrong the system might not boot.

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