Re: [Bug-tar] High per file overhead?

[Joerg Schilling]

Phillip Susi <address@hidden> wrote:

> > As cpio does not offer a -H newc format, let me asume that you are talking  
> >  
> > about the -c or -H crc format...  
> >   
>
> Yes, it does have a newc format, see the info page.  It is also the 
> format used by the linux kernel for initramfs images.

A quick look into the cpio source 
http://cvs.opensolaris.org/source/xref/on/usr/src/cmd/cpio/cpio.c#1216
verifies that there is no such format in cpio.

Maybe you are not talking about cpio but about one of many cpio clones.....


> > du only counts the file contend and a part of the meta data (not counting 
> > e.g.
> > the "inode" - see: /usr/include/sys/fs/ufs_inode.h)
> >   
>
> Right, but the timestamps, owner, and mode only take up a handful of 
> bytes, which cpio also stores.

The cpio archive format -Hcrc never has become a standard and the POSIX cpio 
format
has been declared obsolete 5 years ago because it it not extensible.

Less useful formats may have less overhead but this is an inferior argument
if you have to decide for a portable and extensible format. The POSIX cpio 
format is e.g. limited to 8 GB files and the SVr4 crc format is limiet to even 
less. 

If you like to have an archive format that completely fits your actual needs,
you will end up wit > 100 incompatible archive formats.


> > If you compress the result, the remaining difference is less than 1%.
>
> I'd say archiving my Maildir is a rather real world use, so this is 
> somewhat relevant.  I did notice though, that once compressed, the 
> difference in size is greatly diminished.

See above.

Jörg

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