Backup on DVD-RW: ISO 9660 file system overhead

Hi Debian Users

I am doing a backup of Thunderbird mails. As u can see the Space on disk
is 400 MB less than the space on ISO image.

How can I avoid that much wasted space?

$ du -sh .mozilla-thunderbird/; du -sh mail_archive_20jun08.iso
1.8G .mozilla-thunderbird/
2.2G mail_archive_20jun08.iso

I did the following command:

$ mkisofs -J -r -o mail_archive_20jun08.iso
/home/sjolle/.mozilla-thunderbird/

Did I use the wrong options?

cheers
Simon


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Hello Simon,

You are calculating a little bit wrong, since...

Am 2008-06-21 12:11:51, schrieb Simon Jolle sjolle:
> Hi Debian Users
>
> I am doing a backup of Thunderbird mails. As u can see the Space on disk
> is 400 MB less than the space on ISO image.
>
> How can I avoid that much wasted space?
>
> $ du -sh .mozilla-thunderbird/; du -sh mail_archive_20jun08.iso
> 1.8G .mozilla-thunderbird/

Here you calculate the REAL size of the files and not BLOCK size.

> 2.2G mail_archive_20jun08.iso

This are not only Data, but the Filesystem structure avec TOC too.

And of course, the size if a block on a CD is arround 1500 Bytes

> Did I use the wrong options?

No, since you have a little bit wrong calculated.

Thanks, Greetings and nice Day/Evening
Michelle Konzack
Systemadministrator
24V Electronic Engineer
Tamay Dogan Network
Debian GNU/Linux Consultant


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