Re: OT: Comparison of filesystems

[John O'Hagan <johnohagan@iprimus.com.au>]

On Friday 28 April 2006 03:14, Mike McCarty wrote:
> Sumo Wrestler (or just ate too much) wrote:
> > Ron Johnson wrote:
> >> [...]
> >> Besides, you can't "wipe" files on a journaling fs.  So, you re-
> >> mount your ext3 partition as ext2, wipe the file(s) and then re-
> >> mount as ext3.
> >> [...]
> >
> > Huh?
> >
> > Are you suggesting that you can't permanently delete a file's data by
> > overwriting the file before deleting it?
>
> That's not a suggestion, that's a fact of life with all
> journaling file systems I'm aware of.
>

This quote from man shred may be relevant to this topic:

"CAUTION:  Note  that  shred  relies on a very important assumption: that the 
file system overwrites data in place.  This is the traditional way to do  
things,  but many  modern  file  system designs do not satisfy this 
assumption. [...]  
 " In the case of ext3 file systems, the above disclaimer applies (and shred 
is thus of limited effectiveness) only in data=journal mode, which journals 
file data  in addition to just metadata.  In both the data=ordered (default) 
and data=writeback modes, shred works as usual." 

So apparently one can delete files (at least with shred) from ant ext3 
filesystem as long as the data itself is not journalled.

Cheers,

John