For DVD image "jigdo", template file is about 20% of image size

[Carthik Sharma]

Dvd "jigdo" teplate file for DVD image has size about 650MB. I am not sure if this is real problem; it could be result of jigdo design. But for DVD image is template too big; for CD template is about 1.5MB, it is 0.2% of size of CD image. For DVD image, template file is about 20% of image size!

[psl (slansky)]

Debian jigdo template files for DVD have size about 9MB, that is about 0.3% of image size. This is evidence that Ubuntu generates jigdo template for DVD images in wong way; yes, Ubuntu jigdo file and template for DVD are ok, they work. But they are too big and Debian shows that they could be significantly smaller.

[Philip Paquette (pcpaquette)]

Setting package to jigdo, so this bug gets out of the list of bugs without a package.
Can you confirm this bug still happens in edgy/feisty?
Thanks.

[psl (slansky)]

I think that jidgo files were already removed as these were too big and it is more efficient to use bittorents for DVDs. I undestand that source of problem is big commpressed file stored on DVD, file with root fs for live DVD.

[Colin Watson (cjwatson)]

I'm afraid nothing can really be done about this. The reason the .template is so big is that it has to include the squashfs on the DVD (basically the bulk of the desktop CD). Jigdo doesn't know how to construct a squashfs out of .debs, which is no wonder because it's a filesystem constructed by installing all the packages and a few other things and then running mksquashfs over it. Jigdo can deal fine with ISO9660 images because they just have the .debs plugged into them at known offsets, whereas this isn't at all the case with squashfs images and can't be made to be the case without essentially writing a new set of tools to do it.

Even though it's not as good as it might be, Jigdo is still a useful download method here; the .template should rsync well against previous versions, and failing that it still substantially reduces the amount of download from heavily-loaded DVD mirror sites.

[Colin Watson (cjwatson)]

Debian isn't including live filesystem images on its DVDs, so its template files are not comparable.