Jacob Elder <[EMAIL PROTECTED]> [2002-10-31 14:21:52 -0500]:
> So what is the idiomatic way to guess the size of an archive before writing
> to tape?
The silence has been deafening. Probably everyone else is busy and so
I will jump in again.
> [...previously...]
> df reports that I'm using 2882M.
> tar --exclude-from says that the backup is 2722M.
> du with my tar-friendly exclude from reports that I'm using 2942M.
> du without any exclude file reports that I'm using exactly: 2942M.
I am not sure of the accuracy you wish. To my mind those numbers are
all "close enough" and I would have been happy with that level of
detail.
If you need to know exactly then I can think of no way other than
simply looking at the size of the tar archive. I realize this seems
like a lot of overhead. It is a lot of overhead. Hopefully someone
else will think of a better way. But I know not the overhead factor
that tar needs in order to store files in a tar file enough to be able
to predict exactly the size of the archive.
tar cvzf - $backuplist | wc -c
Recently I posted a snippet to count up the bytes in all files in a
directory tree. Perhaps this is useful.
find $backuplist -print0 | xargs -r0 ls -ld | awk '{sum+=$5}END{printf "%d\n", sum}'
You would probably need to play around with '-type f' and '! -type d'
and your exclude options in order to get a list that was the same and
generated a representative sized tar file. Directories should
probably be excluded from this prediction.
Bob
_______________________________________________
Bug-fileutils mailing list
[EMAIL PROTECTED]
http://mail.gnu.org/mailman/listinfo/bug-fileutils
