Redhat – Does `mkisofs` modify the boot image and/or boot catalog

anacondaisokickstartredhat

I've been playing around with Kickstart on RHEL 6.2, and that involves re-mastering the install ISO. I've noticed something strange, though. If I issue the following command once (where diskFiles is the directory I've kept the DVD files)…

mkisofs -o file.iso -b isolinux/isolinux.img -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -R -J -v -T diskFiles/

…I can't create a working ISO again unless I use a fresh copy of the DVD files. Errors can range from isolinux failing to boot to Anaconda not finding the RHEL install image. So, here's my questions:

  1. Are the isolinux files within my diskFiles directory getting modified when I create the ISO?
  2. If so, what files should I replace whenever I try creating another ISO? I know copying the entire DVD over again works, but it seems unnecessary.
  3. If not, is there something I might be missing in the process that would explain this?

Essentially, my question is this: How is mkisofs doing its magic, and what does it do to the boot image in the process?

Best Answer

1 ) If the files in the diskFiles directory are being modified then this will show up with simple tools such as ls. If you have many files and or sub directories then find is your friend.

2) Rsync from a backup of the DVD will be a lot faster. I do not recommend this because it is a workaround. Finding what causes the problem is almost always better. However I recognise that sometimes a workaround is needed to get things done NOW. My experience is that these workaround stay in place forever, so avoiding them when possible is best.

(skipping item 3 because I have no answer for that).

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