This tool provides a quick analysis of shared space usage between trees of hard-linked files.
For example, if using rsync with the --link-dest parameter to take
full-system backups, this creates fairly large trees that each
superficially (e.g. with du) appear to be the size of a single
full-backup. The total of all the trees is much smaller, as typically
there is massive sharing of data between them. Concisely answering
the question of how much data is shared or unshared within a specific
tree-root is difficult to do without more specialized tools.
This is that tool.
$ time sudo dist/build/shared-space/shared-space /tbackup/chrysalis-201*
Root: FilePath "/tbackup/chrysalis-20150722-222942Z/"
unshared file count: 47.29 k
unshared file size: 10.27 GiBytes
unshared dir count: 93.46 k
unshared dir size: 376.41 MiBytes
shared file count: 521.67 k
shared file size: 205.09 GiBytes
Root: FilePath "/tbackup/chrysalis-20150807-194733Z/"
unshared file count: 35.66 k
unshared file size: 5.23 GiBytes
unshared dir count: 95.91 k
unshared dir size: 386.63 MiBytes
shared file count: 563.37 k
shared file size: 221.06 GiBytes
Root: FilePath "/tbackup/chrysalis-20151018-082220Z/"
unshared file count: 117.30 k
unshared file size: 30.46 GiBytes
unshared dir count: 68.37 k
unshared dir size: 278.55 MiBytes
shared file count: 486.38 k
shared file size: 170.71 GiBytes
Root: FilePath "/tbackup/chrysalis-20160310-182623Z/"
unshared file count: 265.30 k
unshared file size: 63.79 GiBytes
unshared dir count: 75.21 k
unshared dir size: 305.50 MiBytes
shared file count: 377.64 k
shared file size: 134.94 GiBytes
Grand total:
unshared file count: 465.56 k
unshared file size: 109.77 GiBytes
unshared dir count: 332.96 k
unshared dir size: 1.31 GiBytes
shared file count: 614.33 k
shared file size: 226.64 GiBytes
real 0m52.998s
user 0m45.204s
sys 0m7.720s