Plan 9 style backup utility for FreeBSD?

[Eric Rescorla]

I'm finally getting to the point where my disk capacity massively
outruns my tape capacity, so I'm thinking of converting to removable
disk-only backup. I could just use Amanda to backup to disk, but I'm
intrigued by Plan 9's archival filesystem where backups from (say Jan 1,
1999) would go in /1999/1/1 and you could just find the files directly
rather than grovelling through dump files. 

Is there some standard tool for doing this on FreeBSD?  You can't just
do a direct copy cause this results in major disk space wastage so I'm
imagining you need to use hard links or something to keep the size down.

Thanks,
-Ekr