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Date: Tue, 17 Feb 2009 00:39:22 +0000
From: Jamie Lokier <jamie@shareable.org>
To: Adrian Hunter <ext-adrian.hunter@nokia.com>
Subject: Re: [UBIFS] Filesystem capacity
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Cc: "Adam S. Turowski" <a.turowski@wb.com.pl>,
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Adrian Hunter wrote:
> Adam S. Turowski wrote:
> > jffs2:
> > nor: 28361 kB
> > nand: 31200 kB
> > 
> > [ubifs]:
> > nor: 26960 kB (I can live with that)
> > nand: 23552 kB (With that I cannot)
> 
> It is because the LEB size is relatively small, and UBIFS does not
> fit data into the ends of eraseblocks the way JFFS2 does.  Your options
> are:
> 	1. use JFFS2
> 	2. amend your NAND driver to pretend that eraseblocks are bigger
> than they really are, by treating 2 (or 4 or 8 etc) as one eraseblock
> 	3. create another MTD driver that sits on top of the NAND driver
> and does the same as 2
> 
> The disadvantage of 2 or 3 is that it also multiples the effective number
> of bad blocks.

Is this a major flaw of UBIFS?  I was thinking of using UBIFS for a
project but this makes me wonder if it's a good idea.

What does "UBIFS does not fit data into the ends of eraseblocks the
way JFFS2 does" mean?

Thanks,
-- Jamie