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Date: Tue, 19 Jan 2010 10:50:24 +0100
From: Matthias Kaehlcke <matthias@kaehlcke.net>
To: Johnny Hung <johnny.hacking@gmail.com>
Subject: Re: mount ramdisk rootfs /etc directory to jffs2 filesystem.
Message-ID: <20100119095024.GD16182@darwin>
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El Tue, Jan 19, 2010 at 05:20:53PM +0800 Johnny Hung ha dit:

> I have build an embedded Linux system and rootfs is a ramdisk. Ramdisk
> rootfs resides in memory so modify files is non-effective after a
> reboot. Some directories in rootfs, like /etc, /usr, ... are contain
> many application configuration files and I want to mount it to jffs2
> flash filesysyem so it will take effect after a reboot. Is it
> possible?

yes, this is possible

> I know the flash has write times limited so the log files
> (syslogd/klogd) should not store in flash. In general, how to deploy
> root file system for embedded linux with flash storage?

- add jffs2 support to your kernel
- create your image using mkfs.jffs2 from mtd-utils
- flash the image
- specify the rootfs partition and type in the bootargs of the kernel

for further information i recommend the lecture of
http://free-electrons.com/doc/flash-filesystems.pdf

depending on your requirements/size of the rootfs partitions UBIFS
might be an option to consider

-- 
Matthias Kaehlcke
Embedded Linux Developer
Barcelona

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