Saturday, June 6, 2009

Fedora Live USB and Persistence

The disk of my 5 year old machine failed. I wanted to explore the possibility of using it from a 2GB flash disk. The liveusb creator of Fedora with persistence seemed very convenient. All I needed was a second machine to browse the net and use my primary desktop with ssh.

I wanted to add the usual multimedia applications and the persistence filesystem proved very flaky. Even backing up the persistence snapshot and installing rpm's - a few at a time did not work. The snapshot was repeatedly marked as bad.

Since the problem is likely to be the old hardware, a better workaround was needed. I did not wish to create a new live image from scratch.

I extracted and mounted the LiveOS image on the desktop and then add the desired packages to them. The steps were:

$ cp path-to-usb/LiveOS/squashfs.img .
$ sudo mount -oloop squashfs.img /mnt

Now extract the files from the squash file system
$ sudo cp -r /mnt live
$ sudo umount /mnt

Mount the ext3 image used by the LiveOS
$ sudo mount -o loop live/LiveOS/ext3fs.img /mnt

Add the repositories for rpmfusion as per http://rpmfusion.org/Configuration but adding the root option.
$sudo rpm --root=/mnt -Uvh http://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-stable.noarch.rpm http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-stable.noarch.rpm

Now, it was simple to use yum
$sudo yum -y --installroot=/mnt install gstreamer-plugins-bad gstreamer-plugins-ugly

The new squashfs can now be created

$ mksquashfs live squashfs.img

Finally, the new squashfs can be copied to the flashdisk.
As a precaution, I recreated the overlay file, e.g. a 256MB file as below

$dd if=/dev/zero of=overlay-FEDORA-6EB6-DB4C bs=1M count=256

I liked the Fedora 11 beta liveusb, but somehow, I could not get ssh -X to work with my Fedora 10 desktop. I will wait to try again but after the official release so that I can update the desktop as well.

Ubuntu uses a different mechanism for creating persistent storage on the USB disks. I plan to explore that as well and see if that is less flaky on my hardware.

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