Re: [Bug-tar] Use posix_fadvise to improve archive creation performance

[Uwe]

On 03/30/17 20:34, Ralph Corderoy wrote:
>>> I think it would be a good idea to add an option to tell tar whether
>>> to use POSIX_FADV_NOREUSE, POSIX_FADV_DONTNEED, or neither, since
>>> there may be cases where any of the three possibilities is best.
[...]
> I often want to run tar, sha1sum, grep, etc., on a huge file knowing
> that I won't do it again soon and I don't want it bullying the nice
> working-set cache out the door.  It seems crazy every command has to add
> options to twiddle POSIX_FADV_NOREUSE, like dd(1)'s nocache [io]flag
> IIRC.  We have stdbuf(1).  Perhaps a similar approach can be used to
> affect command, even if it can't work in all cases.
> 
>     fadvise --noreuse sha1sum big.foo

FWIW, there is https://github.com/Feh/nocache which I use in a tar
wrapper script for the backup software.

Yours, Uwe