Re: DVD-R as backup medium: growisofs + udftools
On Nov 27, 2007 10:42 PM, Joerg Schilling
<Joerg.Schilling@fokus.fraunhofer.de> wrote:
> > Plextor PX-810SA
>
> This is on the label, but who did make the drive?
Pioneer DVR-212 (see Thomas Maguin, I myself didn't know).
> > >> To start I thought about using packet writing / udftools. By reading
> > >> documentation, it states that I have to
> > >
> > > Wny?
> >
> > I wanted to mount the media as rw and give its mountpoint to flexbackup as
> > 'standard' directory.
>
> Dealing with Write once media is not simple and many use cases do not match.
> Another problem is the filesystem. I am not sure whether UDF is the right
> filesystem. I did not have the time to check UDF but I suspect that
> it is worse than my wofs (designed in 1989) which is the first 100% Copy on
> Write filesystem. From my design and implementation I know the limitations..
>
> If you cannot describe the exact behavior of the backup program it is hard to
> impossible to tell whether the software is compatible with COW filesystems on
> Write once media.
I tried to use mkudffs directly with:
cvsserver:~# mkudffs --udfrev=0x0150 --spartable=2 --media-type=dvd
/dev/pktcdvd/0
Result is:
trying to change type of multiple extents
And the command does not work
> > > Why don't you just write using mkisofs and cdrecord?
> >
> > Definitely next step but follow this:
> > <ideal world>
> > mount -o rw /dev/sr0 /mnt/x
> > flexbackup writes to /mnt/x directly using udf/packet
> >
> > <real world>
> > flexbackup writes to a directory
> > mkisofs /directory |cdrecord
> >
> > In real world I need to make room for temporary backup files, which I thought
> > I could avoy
>
> It is _impossible_ to do correct backups without additional disk space.
Fine. But I was trying to avoid SO MUCH disk space.
Some disk to keep track of what goes in the backup is fine. You say it
is necessary to store star archives on a filesystem prior to backup?
Of course yes, if I do it the mkisofs way, hope not if I use udf +
packet writing.
> If you like to do backups 100% correct, you need filesystem snapshots.
> After you created a snapshot, you run mkisofs -print-size, then you run
> mkisofs /directory |cdrecord tsize=xxx.
>
> Before you start using other software for backups, you need to check whether
> the backup works at all. If you make e.g. incremental backups from full
> filesystems using star, this has been verified to work. If you use anything
> based on GNU tar, you should know that there are many bug reports against
> incremental restores with GNU tar that never have been verified.
flexbackup (to handle timestamps), afio (to create the archive)
I may use star as well, of course
--
Giuseppe "Cowo" Corbelli ~\/~ My software: http://cowo.yoda2000.net
-<! Non c'e' niente da dire in proposito. Tutto quello che uno deve fare e'
colpire i tasti giusti al momento giusto, e lo strumento suona da solo. !>-
J.S. Bach
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