Massive overhead even after deleting checkpoints

["Felix E. Klee" <felix.klee@inka.de>]

The disk is full close to the max:

    $ df -h /bigstore/
    Filesystem            Size  Used Avail Use% Mounted on
    /dev/mapper/bigstore  3.5T  3.3T   65G  99% /bigstore

Yet, not that much is actually used by the files themselves:

    $ du -sh /bigstore/
    2.5T    /bigstore/

Using `rmcp` I deleted all checkpoints, but that didn’t solve the issue.
Furthermore, there are no snapshots:

    $ lscp
             CNO        DATE     TIME  MODE  FLG      BLKCNT       ICNT
          443574  2025-01-10 16:41:44   cp    -    652100924     421961
          443575  2025-01-10 16:41:44   cp    -    652100923     421960

The cleaner daemon is running with default configuration (Arch):

    $ ps ax | grep -i cleanerd
        827 ?        S      0:39 /sbin/nilfs_cleanerd
/dev/mapper/bigstore /bigstore
     117067 pts/1    S+     0:00 grep --color=auto -i cleanerd

I also rebooted the system, causing a remount of the partition. Yet,
still no improvement.

Is there a solution, or is the missing space simply used up by NILFS
data structures? (it would be a bit very much overhead)