Root Filesystem Quotas

Rocky Linux Help & Support
1

I’m attempting to enable quotas in the root filesystem (i.e. /) on Rocky Linux 10. My root filesystem is XFS.

I had been doing this successfully in el9, el8, and probably el7 with the following procedure:

  1. Edit /etc/default/grub; add rootflags=pquota,uquota to the GRUB_CMDLINE_LINUX line.
  2. Run grub2-mkconfig -o /boot/grub2/grub.cfg
  3. Reboot
  4. (Root filesystem now has quota support.)

But I have had no success with this on Rocky 10.

2

I think I’m partway there and hopefully on the right track.

There are some .conf files under /boot/loader/entries that have the kernel command line that was actually used (i.e. the rootflags argument is missing). The info I’m finding says files are supposed to be updated with grubby.

3

First, the kernel cmdline option management did change already in RHEL 9.3, so it is not new to el10.
The current (two) ways are described in Chapter 4. Configuring kernel command-line parameters | Managing, monitoring, and updating the kernel | Red Hat Enterprise Linux | 9 | Red Hat Documentation

That is, if using mkconfig:

grub2-mkconfig -o /boot/grub2/grub.cfg --update-bls-cmdline

The grubby way:

grubby --update-kernel=ALL --args="rootflags=pquota,uquota"

Second, If you would add the pquota,uquota to /etc/fstab for /, would they not affect? Do they have to be on the cmdline options?

4

Thank you, especially for the relevant documentation link.

I tried the grub2-mkconfig command and the quota options were applied successfully.

Adding the quota options for / to /etc/fstab hasn’t worked to enable quotas (at least for XFS on elx) for quite some time. It’s a peculiarity of the root filesystem – the /etc/fstab options work fine for everything else. I didn’t dig up the original explanation I found, but my notes show that I first ran into this back in 2017, so it would have definitely been CentOS 7.

5

The initramfs ought to have copy of fstab, but yes, the root ain’t like everything else.

I have seen (CentOS 7?) cloud images, where the /etc/fstab said “xfs”, but the actual filesystem was something else, so clearly fstab was there “more what you’d call ‘guidelines’ than actual rules”.

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