Appropos my "laughably small" disk space comment, here's a snippet from
mkfs.ext4:

       -m reserved-blocks-percentage
              Specify the percentage of the filesystem blocks reserved for
the
              super-user.   This  avoids  fragmentation, and allows
root-owned
              daemons, such as syslogd(8), to continue to  function
 correctly
              after non-privileged processes are prevented from writing to
the
              filesystem.  The default percentage is 5%.

I have several 12 TB disks scattered about my house. 5% of 12TB is 600GB.
I'm pretty confident that all the spinning (no, tapes aren't spinning)
storage at all of Bell Labs in 1975 was less than the reserved space for
one of my disks. FWIW, I set "-m 0" for honker disks. -- jpl