The half-assed way MS is doing it is a hack.  What you probably really want 
is true snapshots which are done at the FS level. Check out NetApp for an 
example...snapshots are VERY handy and VERY fast way to save yourself from 
having to go to tape. (ie. <1sec to snapshot a 0.5TB filesystem)  The 
snapshots also take no space to speak of (couple megs) until you have a 
delta from the snapshot filesystem contents and the current contents since 
they refer to the same files until it changes/moves/gets deleted/etc.

Snapshots do not protect against device failures due to their nature, but 
they are great ways to do incremental backups in a very short amount of 
time.  They also allow you to rollback to some previous state in about 
1sec.  To overly simplify it: they snap a picture of the filesystem layout 
at a given time and make it static.  All changes after that to existing 
files go to a new place on the disk, leaving the old as it was until you 
free it.  As far as a nice UI, I'd be 100% against that...someone can build 
one but I want file-system level availability:

cd ~
ls
<your current files>
cd .snapshot-062503-1500
ls
<your files as they were on 6/25/03 @ 15:00>
cp <accidentlly deleted file> ~

You just recovered your accidentially deleted file from a snapshot back to 
your home directory.  It's not quite that simple as snapshots are done on 
the filesystem level and not (normally) on the directory level...you might 
have to cd /home/.snapshot-xyz/<username>, but it gets the point across.

I believe this is currently available with LVM but I am unsure of it's 
status.

Of course, another option is to use a versioned filesystem, but thats 
something else from snapshots entirely.

-Rob


On Fri, 27 Jun 2003 12:04:15 +0200, Buchan Milne wrote
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> Greg Meyer wrote:
> > On Thursday 26 June 2003 02:42 pm, Keld J�rn Simonsen wrote:
> >
> >
> >>Anyway I am not interesed in mimicking what MS does, but in something
> >>that is useful and convenient to the average MDK user.
> >>
> >
> > I personally don't find this useful.  When I delete a file, I want it
> to be
> > deleted.  That, in combination with incremental rotating backups I do
> every
> > four hours with rsync give good production and online availability of
> a file
> > if deleted by accident.
> 
> Anyway, one point here is that it is useless implementing something like
> this if there is not a really good consistent UI for it.
> 
> One thing users hate about Windows is it hiding what it does, and at
> present we aren't any better.
> 
> Maybe before adding new incomprehensible features (ie ones without a
> good UI), we should have UIs for the incomprehensible features we
> already have.
> 
> ACL support in Konqueror/Nautilus would get my vote.
> 
> When rollback is available in at least one filesystem (probably Reiser4
> some time after kernel 2.6.1 is out) it may be worthwhile adding a UI
> for it. In the meantime, let's get ACL support back in ext2/3, and have
> a UI for it.
> 
> Regards,
> Buchan
> 
> - --
> |--------------Another happy Mandrake Club member--------------|
> Buchan Milne                Mechanical Engineer, Network Manager
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