OCFS2 and tar sparse files

Hi,

 

In the context of Oracle VM (x86), where most of our files are large and sparse files (img disk files), we'd like to use tar efficiently (i.e using --sparse option).

The drawback is that files are apparently read twice. According to the GNU tar documentation, this is probably due to lack of support by the OS and/or FS

 

abstract from https://www.gnu.org/software/tar/manual/html_node/sparse.html

"

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However, be aware that `--sparse' option may present a serious drawback. Namely, in order to determine the positions of holes in a file tar may have to read it before trying to archive it, so in total the file may be read twice. This may happen when your OS or your FS does not support SEEK_HOLE/SEEK_DATA feature in lseek (See `--hole-detection', below).