fedora on a flash drive

[David Woodhouse]

On Mon, 2005-03-07 at 14:31 -0800, Florin Andrei wrote:
> Why Flash? The OS must survive power crashes and other nasty events
> without ever failing. 

I would recommend that you don't use Compact Flash. Most Compact Flash
cards just aren't that reliable. Do some powerfail testing --
automatically cut power to a live system very few minutes for a week or
two. See what happens.

> Q1: Do you think it's too crazy a project to fly? :-)

No, plenty of people do it -- just not with CF :)

> Q2:
> Ideally, /etc should be on the Flash, along with other config-specific
> directories. Flash has a problem with being written too often, but all
> configs must stay on the Flash for reasons mentioned above.
> Actual question: which directories would you put on the Flash in such a
> situation? (besides /etc)
> Also, /etc has some files which are written to quite often. How would
> you get rid of those?

Take a look at the Familiar distribution for ideas on this
(http://familiar.handhelds.org/). They handle it by using symlinks into
a ramfs /var as appropriate, and untarring the initial contents of that
ramfs in a /linuxrc script.

> Q3: Are there any filesystems that are better for Flash, in that they
> "spread" the writes across multiple blocks?
> Ext3 and any other journalised FSs should be avoided, right? (due to
> concentrating lots of writes in the journal)

For CF or other devices which don't really appear as flash but instead
pretend to be a block device, there's not a lot you can use which makes
much sense. For _real_ flash you'd use JFFS2.

-- 
dwmw2