UBIFS and MLC NAND Flash
dedekind1 at gmail.com
Thu Apr 8 04:22:41 EDT 2010
On Mon, 2010-03-22 at 12:57 -0400, Pedro I. Sanchez wrote:
> I have a few questions regarding this topic.
> 1. The UBIFS FAQ has a summary of the state of the support for MLC NAND
> flash here:
> The question is, is this still the case? Does the FAQ reflect the
> current state of affairs?
I think so.
> 2. I have several boards with MLC NAND flash running the Linux kernel
> 2.6.29 and UBIFS. I am seeing a fairly large rate of file "corruption"
> errors, files that all of a sudden become unreadable. Curiously enough,
> they have been read-only files in all cases, program executables and
> shared libraries.
Hmm. Do you do unclean power cuts?
> Would upgrading to a more recent kernel, or back porting the latest
> UBIFS code, help? Shall I expect better support for MLC NAND flash in
> the latest UBIFS code?
You did not specify whether you pulled the ubifs-v2.6.29.git tree. If
you did this, then your UBI/UBIFS should be the same as in the latest
kernels. Please, do this, although this will probably not solve your
corruption problems, but you'll have other bug-fixes we have made since
Please, take a look here as well:
Did you run MTD tests? If no, run them. You may have issues on driver/HW
Vs. "Shall I expect better support" - not as far as I know, because I
have not heard if anyone is working on this. But you could do that and
> 3. I am also seeing other errors where it is the U-Boot or the Kernel
> partitions that become corrupted. UBIFS is not involved there directly
> since these partitions are at the mtd level and outside the UBI layer.
> More specifically, my flash is partitioned as mtd0, mtd1, mtd2, mtd3,
> mtd4. Only mtd4 has UBI/UBIFS on top. Is it possible that some flash
> handling problems in UBIFS (mtd4) "spill over" other non-UBIFS mtd
May be. Start with validating your MTD driver using MTD tests. This may
help you to narrow down the problem.
> 4. Other than minimizing flash writes, is there any other suggestion on
> what to do to improve on the failure rate I see in the file system?
Not sure. You should carefully investigate you problems and find out the
nature of the failures, and then we can discuss that.
Artem Bityutskiy (Артём Битюцкий)
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