Re: mount ramdisk rootfs /etc directory to jffs2 filesystem.

[Johnny Hung <johnny.hacking@gmail.com>]

2010/1/19 Matthias Kaehlcke <matthias@kaehlcke.net>:
> 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?
>
How to do it? The ramdisk rootfs is ext2 filesystem and I try,
mount /mnt/mtd/etc /etc

Try to modify /etc/ files is not works.

> 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
The above procedure is to create a jffs2 rootfs image but I  prefer to
use ramdisk rootfs.
I think the rootfs is build as ramdisk and some configurable file is
store in jffs2 flash.

Thank your reply.
BRs, H. Johnny

>
> 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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