Re: [PATCH 04/10] AXFS: axfs_inode.c

Jörn Engel
2008-08-22T17:20:30Z

On Fri, 22 August 2008 18:08:51 +0100, Phillip Lougher wrote:
>
> Squashfs stores significantly more metadata than cramfs. Remember
> cramfs has no support for filesystems > ~ 16Mbytes, no inode timestamps,
> truncates uid/gids, no hard-links, no nlink counts, no hashed
> directories, no unique inode numbers. If Squashfs didn't compress the
> metadata it would be significantly larger than cramfs.

Elsewhere in this maze of threads Arnd claimed to have tested the
benefits of metadata compression - and it making little impact.

My guess is that it would make a large impact if metadata would be a
significant part of the filesystem image. Usually metadata is close
enough to 0% to be mistaken for statistical noise. So compressing it
makes a significant impact on an insignificant amount of data.

Jörn

--
One of my most productive days was throwing away 1000 lines of code.
-- Ken Thompson.