The continuous crippling of Fedora LiveCDs by removing usefull stuff for no apparent reason

[Ian Malone]

On 21 December 2015 at 01:17, Chris Murphy <lists at colorremedies.com> wrote:
> On Sun, Dec 20, 2015 at 3:31 PM, Fernando Cassia <fcassia at gmail.com> wrote:
>>
>> On Sun, Dec 20, 2015 at 6:35 AM, Ian Malone <ibmalone at gmail.com> wrote:
>>>
>>> It's neither of these,
>>>
>>> https://fedoraproject.org/wiki/How_to_create_and_use_Live_USB#Data_persistence
>>>
>>> 'currently implemented (as a Device-mapper copy-on-write snapshot),
>>> every single change to it (writes AND deletes) subtracts from its free
>>> space, so it will eventually be "used up"'
>>
>>
>> It confirms what I said: it's broken.
>
> It's not broken. It's working as designed and documented. From
> livecd-iso-to-disk --help
>
> *Note well* that
>         deletion of any original files in the read-only root filesystem does not
>         recover any storage space on your LiveOS device.  Storage in the
>         persistent /LiveOS/overlay-<device_id> file is allocated as needed, but
>         the system will crash *without warning* and fail to boot once the
>         overlay has been totally consumed.  If significant changes or updates
>         to the root filesystem are to be made, carefully watch the fraction of
>         space allocated in the overlay by issuing the 'dmsetup status' command
>         at a command line of the running LiveOS image.  Some consumption of root
>         filesystem and overlay space can be avoided by specifying a persistent
>         home filesystem for user files, see --home-size-mb below.
>
>
>> How about changing the LiveCD creator
>> to allow for "persistent storage" partition that is formatted with F2FS?
>
> Someone needs to volunteer to do the research why that's a better
> option, and include some patches and kickstart scripts so that others
> can test. F2FS does not produce better results just by using it. It's
> highly customizeable/tunable, and it assumes you know things about
> your flash based drive that it can't know (because manufacturer's hide
> this information) so you can tune it. If you don't tune it, you can
> get worse results than just using ext4/XFS/Btrfs or heck even FAT or
> NTFS because the FTL in especially USB flash storage is very well
> tuned for FAT.
>

More than that, the live images are built on squashfs as a compressed
filesystem (would direct Fernando to
https://en.wikipedia.org/wiki/SquashFS), which is where the
requirement to use an overlay to allow persistent storage on root
comes from. There is the option (as I mentioned, removed from the
quote of course) to use a persistent storage image on a normal
filesystem alongside it for home (and whether this is ext4 or f2fs has
nothing to do with the price of fish), but that cannot be done for the
squashfs. So far as I know, you would need to rebuild the image when
creating the live device to allow changing the root filesystem.

If you want a live image with certain packages installed it's not too
hard to roll your own, just create a kickstart file that includes
whatever base kickstart you want and add packages.

-- 
imalone
http://ibmalone.blogspot.co.uk