Re: [mbackup-devel] unix files and holes

[James O'K. <jo...@mi...>]

I think there is a way to find those holes because gnu tar can be smart
and encode those holes in such a way that they don't use up tape. Try
this:

[jokane@lal jokane]$ dd if=/dev/zero of=foo count=1 bs=1k seek=1000
1+0 records in
1+0 records out
[jokane@lal jokane]$ ls -la foo 
-rw-r--r--    1 jokane   505       1025024 Aug 22 15:09 foo
[jokane@lal jokane]$ du foo 
8       foo
[jokane@lal jokane]$ tar cf foo.tar --sparse foo 
[jokane@lal jokane]$ ls -la foo.tar 
-rw-r--r--    1 jokane   505         10240 Aug 22 15:10 foo.tar
[jokane@lal jokane]$ du foo.tar 
12      foo.tar

cool right? :)

-james