[Fedora-livecd-list] RFC- 'persistance' is on LiveCD wishlist- what does it mean?

[Douglas McClendon]

Tim Wood wrote:
> Ideally, for me, there'd be a persistance configuration governing what is
> persistant.  Examples:
> 
> 1) User wants to carry their data with them but not install packages
> 2) Someone wants package persistance
> 3) Someone wants a way to do custom configuration and then lock it down
> 
> 
> So, maybe you can do the following types of things:
> 
> * specify paths that are persistant
> * specify whether those paths are modifiable (e.g. lock it down)
> * specify package persistance
> 


This is actually not as doable for fedora since it uses dm-snapshot overlay 
rather than unionfs for its cow magic.

OTOH, it is doable utilizing the alternate persistence method that I just 
alluded to in the reply to JvM I just sent.  The downside, is that unlike using 
dm-snapshot overlay for persistence, implementing what you described would 
require more user involvement.  I.e. if you go create a file in your homedir, 
then yank the plug on the computer, you would lose the file.  Unlike with 
dm-snapshot-overlay-persistence, in which the file would be there.

Admittedly, I've only given in 2-5 minutes of real thought, but I can't yet 
think of any way to provide that fine grain level of control with 
dm-snapshot-overlay as the persistence mechanism.

Though honestly I'm the sort of person that would say "hey, lets invite unionfs 
back to the party for even more options" :)  (though not for fedora8 
timeframe...  I'm not that crazy ;)

peace...

-dmc



> 
> Maybe looking like this ... using a psuedo syntax that just hit me:
> 
> [persistant paths]
> /home/user(rw)
> /etc(r)
> 
> [persistant packages]
> *
> 
> [persistant options]
> 
> 
> I guess the config would have to exist as say /etc/persistance.conf and be
> part of the persistant archive.  Then joe user could go in, and change the
> /etc entry to (rw), reboot and then update a config file and then lock it
> down again and reboot.
> 
> FWIW, this is somewhat similar to something I hacked together for a
> customized Knoppix disk.
> 
> Timf Wood
> 
> 
> 
> 
> 
> On Thu, 19 Jul 2007 11:25:56 +0200, Jeroen van Meeuwen
> <kanarip at kanarip.com> wrote:
>> Douglas McClendon wrote:
>>> Your preferred use case is certainly as valid or even moreso than the
>>> one I presented.  But having both options seems ideal.  Also, there may
>>> be an issue with usbflash data, and that in some instances it might be
>>> better to have it be mostly preburned as squashfs, rather than treated
>>> as a normal ext3fs.  I.e. the whole jffs2 thing.
>>>
>> Well, I'm not against anything here, I'm sorry if it looked that way. It
>> just doesn't look like it's worth the effort to me personally.
>>
>>> Personally I rather like the idea of having my personal core system on
>>> read-only media, with just my homedir on flash.
>>>
>> Right, that makes sense. A home directory from flash would be nice, but
>> it wouldn't be really 'system persistence' would it? yum install foo and
>> yum remove bar will not have foo and will have bar after a reboot, right?
>>
>> Kind regards,
>>
>> Jeroen van Meeuwen
>> -kanarip
>>
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