choosing a file system to use on NAND/UBI

[Hamish Moffatt]

On Fri, Mar 28, 2008 at 08:33:44AM +0200, Artem Bityutskiy wrote:
> On Fri, 2008-03-28 at 12:04 +1100, Hamish Moffatt wrote:
> > I'm developing an embedded product which will have its root file system
> > on NAND. The root will be pre-prepared and installed using
> > flashcp/nandwrite/ubiupdatevol, and usually mounted read-only.
> > Occasionally we might want to mount it read/write for debug purposes.
> Please, tell the size of your flash and whether it SLC or MLC.

Just to finish this old discussion, it's a 512Mb SLC part. ie not very
big. I have tried UBIFS and I am very pleased with it. Performance is
much better than JFFS2, which was slow to mount and slow during early
reads (even when the image was processed with sumtool).

> > Will ubifs on UBI be better? Is it mature enough to use yet?
> UBIFS mounts very quickly. It is very stable. We find minor issues from
> time to time, but they are fixed quickly.

I noticed that the on-chip format just changed (nanoseconds etc). Do you
plan any more incompatible changes? This is the sort of maturity issue I
was worried about.

> > Would I be better choosing LogFS or YAFFS1/2, perhaps without UBI?
> 
> Never used YAFFSx, but it might be worth trying and evaluating. Vs.
> LogFS - last time we tried it - it was too slow. It also did not
> implement wear-levelling and bad block handling.
> 
> If you try to evaluate them - I would be interested to know about your
> experience.

I could not get a pre-generated YAFFS2 image to mount successfully, and
a call for assistance on the YAFFS mailing list went unanswered.
Although I'm interested in LogFS I don't have enough time to try it
thoroughly.

thanks,
Hamish
-- 
Hamish Moffatt VK3SB <hamish at debian.org> <hamish at cloud.net.au>