Re: [Ltib] Customizing the RFS layout

[Stuart Hughes]

Hi Tony,

On Fri, 2009-01-09 at 09:52 -0800, Anthony L. Montiel wrote:
> I am working on a project in which I plan on having a read-only root
> filesystem. I expect I'll use either CRAMFS or SquashFS. Whichever I
> choose, there is still a requirement for some non-volatile (i.e.
> writeable and persistent) locations in the filesystem (/var for
> example). So I plan on creating a JFFS2 partition in my flash and
> mount that  as /var. I'll use TMPFS for /tmp.
> 
>  
> 
> Questions:
> 
> 1) Is there an example of doing this under LTIB? Specifically,
> creating two filesystems (say CRAMFS and JFFS2) within the LTIB build
> structure.

No, I've not got any examples that output directly to 2 file-systems,
however there's an option under:
Target Image Generation / Options / read-only root filesystem
to make an image read-only.  What this actually does is set a list of
directories that the startup script 'etc/rc.d/filesystems' should move
into tmpfs (ramfs) and then bind mount (normally: /var /tmp /etc).

What you could do is either modify this script to do what you need.
Alternatively you could make a customer rc.local that would setup the
jffs2 rw filesystem and then mount that over the areas that need to be
read/write.  It would need a bit of work.

If you come up with a generic solution to this it would be nice to get
the patch as I think this would be a useful enhancement.

>  
> 
> 2) I am using the i.MX27 ADS release ISO as my starting point. Is
> there any advantage to using a "fresh" LTIB, rather than the
> pre-packaged version?
> 
>  

It depends how old the ISO release is.  If it's fairly recent then it's
fine.  If it's older then it's probably better to use savannah CVS. 

Regards, Stuart