$ time tarsnap --humanize-numbers -c -f mac-virtualbox-20131030 ~/VirtualBox\ VMs/
tarsnap: Removing leading '/' from member names
Total size Compressed size
All archives 131 GB 56 GB
(unique data) 17 GB 6.9 GB
This archive 19 GB 8.2 GB
New data 297 MB 108 MB
real 6m0.835s
user 3m25.115s
sys 0m4.538s