Ideal NAND flashes for JFFS2 or YAFFS

Ideal NAND flashes for JFFS2 or YAFFS

[Joakim Tjernlund]

We are looking into using NAND flash instead of NOR flashes in our design and I am
trying to find out how the ideal NAND flash should look like to be used as a JFFS2 or YAFFS
file system. We are mainly looking for speed and reliability. Power cuts are common
for our boards.

Any suggestions like generic properties or specific chips are welcome.

 Jocke

Re: Ideal NAND flashes for JFFS2 or YAFFS

[Artem Bityutskiy]

On 08/22/2009 11:30 AM, Joakim Tjernlund wrote:
>
> We are looking into using NAND flash instead of NOR flashes in our design and I am
> trying to find out how the ideal NAND flash should look like to be used as a JFFS2 or YAFFS
> file system. We are mainly looking for speed and reliability. Power cuts are common
> for our boards.

Not sure about the FSes, but we are happy with speed and reliability
of OneNAND from Samsung.

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)

Re: Ideal NAND flashes for JFFS2 or YAFFS

[Joakim Tjernlund]

Artem Bityutskiy <dedekind1@gmail.com> wrote on 22/08/2009 10:40:26:
>
> On 08/22/2009 11:30 AM, Joakim Tjernlund wrote:
> >
> > We are looking into using NAND flash instead of NOR flashes in our design and I am
> > trying to find out how the ideal NAND flash should look like to be used as a
> JFFS2 or YAFFS
> > file system. We are mainly looking for speed and reliability. Power cuts are common
> > for our boards.
>
> Not sure about the FSes, but we are happy with speed and reliability
> of OneNAND from Samsung.

Thanks, will look closer at these.

Re: Ideal NAND flashes for JFFS2 or YAFFS

[Joakim Tjernlund]

Artem Bityutskiy <dedekind1@gmail.com> wrote on 22/08/2009 10:40:26:
>
> On 08/22/2009 11:30 AM, Joakim Tjernlund wrote:
> >
> > We are looking into using NAND flash instead of NOR flashes in our design and I am
> > trying to find out how the ideal NAND flash should look like to be used as a
> JFFS2 or YAFFS
> > file system. We are mainly looking for speed and reliability. Power cuts are common
> > for our boards.
>
> Not sure about the FSes, but we are happy with speed and reliability
> of OneNAND from Samsung.

Looking briefly at OneNAND is seems to be a somewhat complicated device with
builtin SRAM and a emulated NOR interface.

Is this really a good fit for FS:es like JFFS2 or YAFFS?

hmm, maybe I should look at UBIFS too :)

 Jocke

Re: Ideal NAND flashes for JFFS2 or YAFFS

[Bill Gatliff]

Joakim Tjernlund wrote:
> hmm, maybe I should look at UBIFS too :)
>   

I'm currently a big fan of UBIFS for NAND.  I'd take a look at it.

I haven't compared it to YAFFS2, but UBIFS is in mainline kernels, where 
YAFFS2 isn't.  That gives UBIFS bonus points for convenience.  And so 
far for me, UBIFS has been really, really solid.


b.g.

-- 
Bill Gatliff
bgat@billgatliff.com

Re: Ideal NAND flashes for JFFS2 or YAFFS

[Artem Bityutskiy]

On 08/24/2009 09:44 PM, Joakim Tjernlund wrote:
> Artem Bityutskiy<dedekind1@gmail.com>  wrote on 22/08/2009 10:40:26:
>>
>> On 08/22/2009 11:30 AM, Joakim Tjernlund wrote:
>>>
>>> We are looking into using NAND flash instead of NOR flashes in our design and I am
>>> trying to find out how the ideal NAND flash should look like to be used as a
>> JFFS2 or YAFFS
>>> file system. We are mainly looking for speed and reliability. Power cuts are common
>>> for our boards.
>>
>> Not sure about the FSes, but we are happy with speed and reliability
>> of OneNAND from Samsung.
>
> Looking briefly at OneNAND is seems to be a somewhat complicated device with
> builtin SRAM and a emulated NOR interface.
>
> Is this really a good fit for FS:es like JFFS2 or YAFFS?

Well, depends. I just told what we used and found to be very fast and reliable.
We even erased one PEB 2000000+ times, and it did not die. But yes, this is a
complex device with HW ECC support, etc.

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)

Re: Ideal NAND flashes for JFFS2 or YAFFS

[Artem Bityutskiy]

On 08/24/2009 09:50 PM, Bill Gatliff wrote:
> Joakim Tjernlund wrote:
>> hmm, maybe I should look at UBIFS too :)
>
> I'm currently a big fan of UBIFS for NAND. I'd take a look at it.
>
> I haven't compared it to YAFFS2, but UBIFS is in mainline kernels, where
> YAFFS2 isn't. That gives UBIFS bonus points for convenience. And so far
> for me, UBIFS has been really, really solid.

Thanks for positive feedback. We were working hard :-)

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)

Re: Ideal NAND flashes for JFFS2 or YAFFS

[Justin Treon]

For NAND I think there is a simple flow chart to pick your filing system.

Do you have a partition bigger than 256 MBytes?
If YES: Use UBIFS (@128 MB you can argue the point)
If NO: Do you have a LOT of RAM?
	If YES: Use YAFFS2 (It is fast, but RAM hungry)
	If NO: Use JFFS2

> I'm currently a big fan of UBIFS for NAND.  I'd take a
> look at it.
> 
> I haven't compared it to YAFFS2, but UBIFS is in mainline
> kernels, where YAFFS2 isn't.  That gives UBIFS bonus
> points for convenience..  And so far for me, UBIFS has
> been really, really solid.
> 
> 

Re: Ideal NAND flashes for JFFS2 or YAFFS

[Bill Gatliff]

Justin Treon wrote:
> For NAND I think there is a simple flow chart to pick your filing system.
>
> Do you have a partition bigger than 256 MBytes?
> If YES: Use UBIFS (@128 MB you can argue the point)
> If NO: Do you have a LOT of RAM?
> 	If YES: Use YAFFS2 (It is fast, but RAM hungry)
> 	If NO: Use JFFS2
>   

With 128MB and/or 1GB partitions, does YAFFS2 use more memory than 
UBIFS?  It does seem to me that YAFFS2 mounts a tad faster, though I 
haven't broken out the stopwatch or anything (yet).


b.g.

-- 
Bill Gatliff
bgat@billgatliff.com

Re: Ideal NAND flashes for JFFS2 or YAFFS

[Joakim Tjernlund]

Bill Gatliff <bgat@billgatliff.com> wrote on 08/09/2009 18:21:58:
>
> Justin Treon wrote:
> > For NAND I think there is a simple flow chart to pick your filing system.
> >
> > Do you have a partition bigger than 256 MBytes?

Oh yes, probably 512MB-1GB, possibly more

> > If YES: Use UBIFS (@128 MB you can argue the point)
> > If NO: Do you have a LOT of RAM?
> >    If YES: Use YAFFS2 (It is fast, but RAM hungry)

This is news to me. I always had the impression that JFFS2 needed
more RAM.

> >    If NO: Use JFFS2
> >
>
> With 128MB and/or 1GB partitions, does YAFFS2 use more memory than
> UBIFS?  It does seem to me that YAFFS2 mounts a tad faster, though I
> haven't broken out the stopwatch or anything (yet).

I too want to know.

 Jocke

Re: Ideal NAND flashes for JFFS2 or YAFFS

[Corentin Chary]

On Tue, Sep 8, 2009 at 8:01 PM, Joakim
Tjernlund<joakim.tjernlund@transmode.se> wrote:
> Bill Gatliff <bgat@billgatliff.com> wrote on 08/09/2009 18:21:58:
>>
>> Justin Treon wrote:
>> > For NAND I think there is a simple flow chart to pick your filing system.
>> >
>> > Do you have a partition bigger than 256 MBytes?
>
> Oh yes, probably 512MB-1GB, possibly more
>
>> > If YES: Use UBIFS (@128 MB you can argue the point)
>> > If NO: Do you have a LOT of RAM?
>> >    If YES: Use YAFFS2 (It is fast, but RAM hungry)
>
> This is news to me. I always had the impression that JFFS2 needed
> more RAM.
>
>> >    If NO: Use JFFS2
>> >
>>
>> With 128MB and/or 1GB partitions, does YAFFS2 use more memory than
>> UBIFS?  It does seem to me that YAFFS2 mounts a tad faster, though I
>> haven't broken out the stopwatch or anything (yet).
>
Hi,

First memory usage as nothing to do with mount time.

UBIFS mount time is small, but UBI scan can take some time (see
http://www.linux-mtd.infradead.org/doc/ubi.html#L_scalability ).
If you use YAFFS2 with checkpoints, after a clean unmount, I believe
that mouting can be faster than UBI+UBIFS.
But it will depend how many dir/files you have. YAFFS2 mount time will
increase lineary with the number of objects stored.



-- 
Corentin Chary
http://xf.iksaif.net

Re: Ideal NAND flashes for JFFS2 or YAFFS

[JiSheng Zhang]

2009/9/9 Bill Gatliff <bgat@billgatliff.com>:
> Justin Treon wrote:
>>
>> For NAND I think there is a simple flow chart to pick your filing system.
>>
>> Do you have a partition bigger than 256 MBytes?
>> If YES: Use UBIFS (@128 MB you can argue the point)
>> If NO: Do you have a LOT of RAM?
>>        If YES: Use YAFFS2 (It is fast, but RAM hungry)
>>        If NO: Use JFFS2
>>
>
> With 128MB and/or 1GB partitions, does YAFFS2 use more memory than UBIFS?
>  It does seem to me that YAFFS2 mounts a tad faster, though I haven't broken
> out the stopwatch or anything (yet).

Once UBI2 implemented, ubi attach + ubifs mount will be faster than
yaffs2. Currently it seems that yaffs2 faster.

B.R,
jisheng