sparse files

[Roger Oberholtzer]

On Wed, 2005-05-25 at 09:24 -0500, Mike Reinehr wrote:
> On Wednesday 25 May 2005 12:37 am, Roger Oberholtzer wrote:
> > > > `tar' ignores the `--sparse' (`-S') option when reading an archive.
> > 
> > I do not see this in my tar's man page. I use tar 1.15. I specify
> > --sparse when tar creates and extracts the archive.
> 
> You haven't mentioned what distribution your using. I'm using Debian & my man 
> page for tar includes this disclaimer:

When creating the archive it has been tar 1.15 on a current Gentoo. When
extracting the file, it was the same, or SUSE 9.2.

I see in the SUSE9.2 info (not man) for tar that --sparse is only
discussed when making an archive. Of course, if you can only archive but
not extract such files, I am unsure of the value of --sparse at all.

In fact, I just want to clone a sparse file on a different system. There
must be a way. I do not require tar. I will next try a 'cp' to the same
partition, and then an NFS copy. I looked into rsync, but it did not
seem that it supported sparse files. As a minimum, any checksumming
should surely fail if the target file is not identical to the source.

And, as luck would have it, there was a power failure some time during
the day and the Gentoo box at home is very unhappy. Both hard disks are
iffy. Could be a power supply. So, it will be a different type of fun
for a while before I revisit sparse file copying.

-- 
Roger Oberholtzer <roger at opq.se>