Mailinglist Archive: opensuse (2912 mails)

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Re: [SLE] Backup to CD/DVD -- recommended software?
  • From: "Carlos E. R." <robin1.listas@xxxxxxxxxx>
  • Date: Sat, 5 Feb 2005 01:21:39 +0100 (CET)
  • Message-id: <Pine.LNX.4.58.0502050051380.9766@xxxxxxxxxxxxxxxx>

The Wednesday 2005-02-02 at 08:24 -0800, Christopher Carlen wrote:

> > > mkisofs -v -R /data | cdrecord -v fs=12 speed=4 dev=ATA:1,1,0 -
> > >
> > > If your a competent script writer (I'm not) you could improve on this by
> > > creating the iso first, burn it, then delete the iso image. That would
> > > nearly eliminate any chance of files changing.
> >
> >
> > With an intermediate step, you can also compress the image. The linux kernel
> > can later mount the compressed cdrom or dvd transparently. I don't know if
> > any gui can do that.
>
>
> Really? That's interesting. How to do this?

...

> So I think what you are talking about is different. The .tgz is not a
> *filesystem* proper, while a compressed ISO is. So I would presume that this
> could work much faster than my attempt at accessing a 500MB .tgz.

Correct. Read access is immediate: just mount the dvd and read any file
directly with any tool: konkeror, cp, mc, whatever. But creating it is
cumbersome.

I do:

1) Create a compressed copy of the files you want to put on the CD/DVD.
For example:

mkzftree --parallelism 3 $SOURCE $DESTINATION.CMP

The destination directory must _not_ exist, the command creates it.
There are not many options, see the man page (mkzftree - Create a
zisofs/RockRidge compressed file tree)

2) Create the iso image. For example:

mkisofs -z -R -quiet -graft-points\
-P "Not Published, private backup" \
-p "Carlos E. R. .... dot es" \
-V "System Backup, Linux" \
-o $DESTINO_ISO $DESTINO_CMP \
download/=/home/cer/download/ \
compilaciones__tars/=/home/cer/compilaciones/_tars/ \
_usr_src_packages_packages/=/usr/src/packages/ \
patches/=/var/lib/YaST/patches/i386/update/7.3/


The only important switch there is "-z". It is added by a patch to the
mkisofs tool, but SuSE has been adding it since just after SuSE 7.3. I
know because at the time I added it manually to test it.

2.5) Delete the compressed tree if you need the space.

3) Burn the image. I use xcdroast for that, but any tool will do.

4) Use the CDrom or DVD - I have tested it for dvds with SuSE 9.1, it
works. The kernel needs zisofs support, but SuSE kernels have it.

There are other compressed filesystems in 9.2, but I haven't tested them
because I haven't updated yet.

The procedure works fine. The problem is that you need a lot of space:
first to create the compressed tree, more than half the original tree.
Then space for the iso images: but you can create one at a time, or on the
fly and burn.

A secondary and not trivial problem is to adjust what to put on each image
so that it is "small" enough to fit in the available media - this is
complicated because no gui knows about zisofs. My trick is to divide the
original compressed tree into several trees, using mc for moving files and
calculating sizes.

So... the overall process is slow. The result is perfect.


A great improvement would be a mkisofs tool that cold compress on the fly.
However, I doubt it could calculate exact size in advance.


Obviously, if you have very large files, bigger than a CD or a DVD, you
can not use this method.


--
Cheers,
Carlos Robinson


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