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abisko00 11-18-2005 04:28 AM

Can't burn KDar backup to DVD (slices too large)
I just created a backup of my homedirectory with KDar. KDar asked me on which medium the slices shall fit, so I selected 4.7GB DVD from the menu. The created slices where 4400MB. But when I try to burn them, I get an error from mkisofs:

growisofs -overburn -Z /dev/sr0 -R -J linux-home.20051117.1.dar
Executing 'mkisofs -R -J linux-home.20051117.1.dar | builtin_dd of=/dev/sr0 obs=32k seek=0'
INFO:  UTF-8 character encoding detected by locale settings.
        Assuming UTF-8 encoded filenames on source filesystem,
        use -input-charset to override.
mkisofs: Value too large for defined data type. File linux-home.20051117.1.dar is too large
:-( write failed: Input/output error

So who is wrong here? KDar, mkisofs or me? Is there a way to get this backup on a single layer DVD? It took half a day to create those files, so I'd like to avoid doing it again.

Paxmaster 11-18-2005 04:14 PM

Yeah for some reason the mkisof cannot burn over 4.2GB

if u want to burn those file i would use split to split the file in 4200000000
good luck

abisko00 11-20-2005 09:04 AM

Tried your suggestion to join the splits and split them again in smaller pieces. Unfortunately KDar does not recognize those files anymore, so I ran another backup with the split-setting on 4200 MB (instead of the default 4400 MB).

Still no luck! k3b refuses to burn these files.

/usr/bin/mkisofs: Value too large for defined data type. File /home/user/backup/linux-home.20051119.1.dar is too large
Any ideas?

madluther 11-20-2005 09:29 AM

You need to keep the file sizes of the slices under the limit of the filesystem you are creating with mkisofs, typicaly a on dvd-r image, that filesystem is UDF and file size limit is 2G.



abisko00 11-20-2005 09:33 AM

This leads to the question if there is a filesystem that allows files larger than 2GB.

What did the developers of KDar have in mind, when they included this option in their software?

madluther 11-20-2005 10:18 AM

You could try manually creating a filesystem that supports larger file sizes...

Assuming a dvd-r can hold 4590208 1k blocks (see here)

create an empty image

dd if=/dev/zero of=test.iso count=4590000 bs=1k
associate the image with a loop device

losetup /dev/loop0 test.iso
create a filesystem on the device

mkfs -t ext2 -N 20 /dev/loop0
mount it ..

mount /dev/loop0 /mnt
Copy the files over, and unmount with

umount -d /dev/loop0
This should give you an image that will hold files as large as 4.3G. Unfortunately I dont know if this will actually be mountable and readable once the image is burnt to dvd-r, I dont have any spare (or re-writeable) media or suitably large files to test it with.



abisko00 11-21-2005 04:18 AM

Thank you very much!!!

This works very well. I followed your instructions exactly and I could write the file to DVD and mount it later.

However, I have to file a big complaint about KDar: KDar refuses to open an archive if not all slices are present on the same medium. This means that for a recovery, I need to copy the whole archive to HDD before I can extract files. This is rather stupid! Together with the confusing DVD split function, this software costed me 4 days without getting a usable backup.

mh11 12-08-2005 04:23 PM


this seam to be a great hint, I also coult burn a DVD (I had the same problem as Abiso00.

But for me, I could not mount the device. What was the exact command, with which you mounted your DVD, abiso?

On the other side, maybe I have a hint for you:
As I tested, KDar does not need to have all slices of the archive, but only the first one and the last (which contains the catalog).

In my opinion, it should be possible to burn DVDs like this:
1. DVD: small first slice (let's say 100MB) and last slice (rest of DVD-space).
2. all other DVDs: slices in DVD-size - 100MB (ok, you loos 100MB, but this is ok for me.

Then, if I want to restore some files, I just put in the first DVD, open the archive, can access the catalog and select one or more files to restore. If the file(s) are not located on this DVD, KDar will ask me to provide the DVD with the correct number, I will put it in the drive and restore the file.

I made this test with some files on my HDD, because I was not able yet to burn them on DVD (burining yes, but not mounting).

Unfortunately I could not finish the tests on my HDD, because KDar do not let you enter a path for the missing archive-slice, but I hope, this will work for DVDs.

abisko00 12-09-2005 03:49 AM

Thanks for the research! I will keep this in mind when I make further backups.

On my SUSE 10.0, the DVD is mounted automatically, but the mount command I used in the test was 'mount -t ext2 /dev/hdc /mnt/backup'

mh11 12-09-2005 05:15 PM

Hi again,

thank you, I solved the problem with mounting the dev.

Do not know, if it was the kernel update (don't think so), the machine reboot or still my awkwardly behaviour.

But I tried to burn the DVDs as mentioned yesterday (DVD1: 1 small slice and last slice), rest DVDs, 1 slice per DVD.

It works great, I just put in DVD 1, open the archive, see the catalog, click on "restore" for the file I want to, KDar asks me to provide the correct DVD, I change them and restore the file.

So next, I will setup an automatic diff backup.
With archive-isolate, I keep the catalog on the HDD, the rest is on DVDs. Then I do with cron a diff backup, which is copied to a DVD and I can access every backups, I want.

I hope, that the KDar guys will implement the function "restoring from an isolated catalog" as they promise on their website, this would make restore's even much more easier than today.

But in a few words, KDar is great (sufficent for private data backups), and, of course, linux is great.

An OT question BTW: any hint, how I can access this "special DVD" with a windows-system (I know, this is a linux forum!)


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