UBIFS recovery fails

[Ivan Djelic]

On Tue, Oct 18, 2011 at 09:11:54AM +0100, Ricard Wanderlof wrote:
> 
> On Mon, 17 Oct 2011, Artem Bityutskiy wrote:
> 
> > [...] Unfortunately, no one really invested time into making UBIFS 
> > support MLC very well. It needs some more work. It also have some issues 
> > related to unstable bits in modern SLC.
> >
> > In short - if you want to use UBIFS on MLC - you should not have unclean
> > reboots. If you want to make UBIFS 100% uclean-reboot save on MLC - you
> > need to work on it some more.
> >
> > We (the original authors) developed and tested it on very robust SLC
> > NAND.
> 
> Do you have any specifics on what the issues are with MLC ?
 
Besides unstable bits, lower endurance, higher ecc requirements and NOP1, there
is a "page pairing" phenomenon which is not handled by UBI/UBIFS AFAIK.
When you cut power during a page write, you may lose data in another (paired)
previously programmed page.

BR,
--
Ivan