You can enable quotas from WHM on a server using XFS with the "Initial Quota Setup" interface.
The server must be rebooted for quotas to be functional.
Access the server's command line as the 'root' user via SSH or "Terminal" in WHM.
Verify that /etc/fstab shows that the uquota option is set for the filesystems on which you want quotas enabled.
# grep xfs /etc/fstab
/dev/mapper/centos_whm1-root / xfs defaults,uquota 0 0
UUID=fe712bf1-6f9f-4f69-950f-add2a660dfd4 /boot xfs defaults 0 0
/dev/mapper/centos_whm1-home /home xfs defaults 0 0
Verify that the filesystems were mounted with quotas enabled.
# mount | grep xfs | grep -v virtfs
/dev/mapper/centos_whm1-root on / type xfs (rw,relatime,attr2,inode64,uquota)
/dev/sda2 on /boot type xfs (rw,relatime,attr2,inode64,noquota)
/dev/mapper/centos_whm1-home on /home type xfs (rw,relatime,attr2,inode64,uquota)
/dev/mapper/centos_whm1-root on /var/tmp type xfs (rw,relatime,attr2,inode64,uquota)
If the filesystems do not show the uquota option, the grub configuration will have to be updated to enable quotas at boot.
Once you verify your XFS filesystem is mounted with quotas enabled, log into WHM as the 'root' user.
Navigate to "Home » Server Configuration » Initial Quota Setup."
Review the warnings on the page.
Click the "Proceed >>" button.
Wait for the setup to complete. You should see output similar to the following once the setup has completed.
The time needed to complete the setup depends on the size of the file system. Larger filesystems will take longer for the setup to complete.
Navigate to "Home » System Reboot » Graceful Server Reboot."
Click the "Proceed >>" button to reboot the server.