dump(8) Period. Elizabeth D. Zwicky
torture tested all the backup programs discussed here. The clear
choice for preserving all your data and all the peculiarities of
Unix filesystems is dump(8). Elizabeth created
filesystems containing a large variety of unusual conditions (and
some not so unusual ones) and tested each program by do a backup
and restore of that filesystems. The peculiarities included:
files with holes, files with holes and a block of nulls, files
with funny characters in their names, unreadable and unwritable
files, devices, files that change size during the backup, files
that are created/deleted during the backup and more. She
presented the results at LISA V in Oct. 1991. See
torture-testing Backup and Archive Programs.