#apt install btrfs-compsize
compsize /storage

root@server5:~# compsize /storage
Processed 2372982 files, 3851354 regular extents (4229108 refs), 356322 inline.
Type       Perc     Disk Usage   Uncompressed Referenced
TOTAL       99%      8.0T         8.1T         9.6T
none       100%      8.0T         8.0T         9.6T
zlib        34%       13G          37G          40G
prealloc   100%      138M         138M         334M

# apt install -y jdupes
jdupes --one-file-system --dedupe --recurse --size /storage/

btrfs filesystem du --summarize --human-readable  /storage/

root@server5:~# btrfs filesystem du --summarize --human-readable  /storage/
     Total   Exclusive  Set shared  Filename
   9.64TiB     6.69TiB     1.41TiB  /storage/