Yes, it was our core design decision. One of the reasons, we were not sure
this is technically possible to do on bare flashes. I mean, it just looked
so complex to have all in one, so we figured that was a good split, where
you can cut on big work on two smaller separate ones. The benefit of this
is obvious - we have created a complete system, which is not perfect though
and have scalability issues.
Our point is that UBI is scalable enough for the time being.
I wrote some documentation about this in UBI FAQ and UBIFS FAQ:
http://www.linux-mtd.infradead.org/doc/ubifs.html#L_scalability
We can now improve scalability of UBI without affecting UBIFS - it has some
potential. And we may develop UBI2 which would be more much more scalable,
but this is a big project and we are not planning to do this so far. Others
could do.
So in other words, using UBI allowed us to get a finished system faster. I
meets our's and many other people's requirements, although it has issues if
you try to use it on really huge flashes, like 64GiB. That's a drawback.
But the good thing is that this would require re-working UBI layer, without
complete re-working of UBIFS.
Agree.
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Best Regards,
Artem Bityutskiy (Артём Битюцкий)
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