Re: Imaging the hard drive?

[John <valhalla@computerdatasafe.com.au>]

On Sunday 11 August 2002 01:15, Jude DaShiell wrote:
> Why not make everybody happy and pipe the dd output into tar with the Z
> option so compressed tar files come out?  Is /proc all that needn't be

That is not how you use tar, and tar will get extremely shirty about it.

You use tar thus:
tar -cl -C / . boot home ...

-c means create
-l means use local filesystems (that is, don't cross mount-points)
-C means change to the specified directory before starting work
Then I named the filesystems to backup. Change to suit your circumstances.



> backed up or do other directory trees exist too?  I could make a little
> script out of this perhaps and share it with the list.  The thing is, it's
> possible to make those compressed tar files land on zip disks which is how
> I'd do it for myself but the thing I'd like to figure out is if tar could
> be told to put a unique disk number into each file it wrote on those zip
> disks.  That way ordering of disks for restore would be easy for blind or
> sighted people.

Zip disks are awfully small, and have these difficulties:
1) Subject to erasure by fluctuating magnetic fields (think mobile phones that 
vibrate)
2) You require a zip drive to read them
3) Are expensive. Did I mention small?

In contrast, a CD burner costs about the same, maybe less that a Zip drive.
In contrast,
1) CDs are immune to fluctuating magnetic fields
2) Can be read in any (reasonably recent) CD drive
3) Are relatively large - over six times the capacity of a 100 Mbyte Zip disk.
4) Are cheap.

I recomment afio (which does not come with RHL) over tar for backup purposes. 
You can specify the volume size for both, and you can run a user script at 
enf-of-volume for each, but the size you tell tar is the size of the 
uncompressed data whereas afio understands the size you tell it is the amount 
of compressed data to write.


> 
> On Tue, 19 Mar 2002, Janina Sajka wrote:
> 
> > You're correct, Mike. dd will write an exact byte by byte image. He was
> > asking about Ghost, and I think this would be the analog to Ghost. tar is
> > also an excellent choice, however.
> >  On Tue, 19 Mar 2002, Mike Gorse wrote:
> >
> > > Janina, I am not sure that that would work well for what he wants to do.
> > > I would not trust dd to make an image of a file system for the purpose 
of
> > > transporting it to another computer which may have a different hard disk
> > > and a Linux partition of a different size.  Tar should work well, 
however,
> > > so long as you pass it parameters to exclude anything that you do not 
want
> > > copied (ie, /proc).
> > >
> > > -- Michael Gorse / AIM:linvortex / http://mgorse.home.dhs.org --
> > >
> > > On Mon, 18 Mar 2002, Janina Sajka wrote:
> > >
> > > > Imaging in linux is the easiest imaging you will ever do.
> > > >
> > > > Use the dd command partition by partition as follows:
> > > >
> > > k
> > >
> > >
> > >
> > > _______________________________________________
> > > Blinux-list mailing list
> > > Blinux-list@redhat.com
> > > https://listman.redhat.com/mailman/listinfo/blinux-list
> > >
> >
> > --
> >
> > 				Janina Sajka, Director
> > 				Technology Research and Development
> > 				Governmental Relations Group
> > 				American Foundation for the Blind (AFB)
> >
> > Email: janina@afb.net		Phone: (202) 408-8175
> >
> > Chair, Accessibility SIG
> > Open Electronic Book Forum (OEBF)
> > http://www.openebook.org
> >
> >
> >
> > _______________________________________________
> > Blinux-list mailing list
> > Blinux-list@redhat.com
> > https://listman.redhat.com/mailman/listinfo/blinux-list
> >
> 
> 
> 
> _______________________________________________
> Blinux-list mailing list
> Blinux-list@redhat.com
> https://listman.redhat.com/mailman/listinfo/blinux-list
> 
> 

-- 


Cheers
John.

Please, no off-list mail. You will fall foul of my spam treatment.
Join the "Linux Support by Small Businesses" list at 
http://mail.computerdatasafe.com.au/mailman/listinfo/lssb