rsync --link-dest, --delete and hard-link count

[grarpamp]

I goofed up one part of this:

Since things are stored in hierarchy, not flat... it's not the sum
of all the full pathnames. But the sum of the names in each directory
and the sum of all those sums. Adjust theory minimums accordingly.

Still can use great gobs of space though, easily overlooked.

And at least on these FS's, the cost lies among the total number
of dirs/files and their langth.

{00..00}/{00..99}/{00..99}
find . | wc 10102 lines 110807 chars
MFS: du -cks 20204
ZFS: du -cks 85867

{00000000000..00000000000}/{00000000000..00000000099}/{00000000000..00000000099}
find . | wc 10102 lines 382616 chars
MFS: du -cks 20406
ZFS: du -cks 61835

{1x<255chars>}/{100*<255chars>}/{100*<255chars>}  # 0123456789 * 25.5
find . | wc 10102 lines 7751660 chars
MFS: du -cks 25052
ZFS: du -cks 89923

{000..000}/{000..009}/{000..999}
find . | wc 10102 lines 140108 chars
MFS: du -cks 20124
ZFS: du -cks 62526

{00000..31999}
find . | wc 32001 lines 256002 chars
MFS: du -cks  64528
ZFS: du -cks 276153

{00000..31999}  # not mkdir, touch $i
find . | wc 32001 lines 256002 chars
MFS: du -cks   528
ZFS: du -cks 20153

{00000..20000}  # not mkdir, touch <240 0 chars>$i
find . | wc 20002 lines 4960250 chars
MFS: du -cks  5024
ZFS: du -cks 14185

UFS: numbers same as MFS, only much slower
ZFS: seems to make some adjustments on subsequent runs
ALL: these FS's were quite full