[Bug-tar] O_DIRECT support for tar?

[Jim Meyering]

Hello,

Have you considered adding O_DIRECT support to tar?
I'm writing this because I see my system's buffer cache is being rendered
essentially useless while I'm streaming (via tar) 10GB to tape.  If the
O_DIRECT attribute were in effect for all of those reads, then I suspect
that the impact on interactive users like me would be negligible.

For an example of how this was done for GNU shred, see

  <http://lists.gnu.org/archive/html/bug-coreutils/2004-06/msg00044.html>

GNU dd (in post-5.2.1 coreutils -- i.e., in the cvs repository) also has
options to enable direct-mode I/O.

Jim