Ideal NAND flashes for JFFS2 or YAFFS

[Corentin Chary]

On Tue, Sep 8, 2009 at 8:01 PM, Joakim
Tjernlund<joakim.tjernlund at transmode.se> wrote:
> Bill Gatliff <bgat at 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