Updated UBIFS 8.2 image

Deepak Saxena dsaxena at laptop.org
Tue Oct 14 18:31:27 EDT 2008


On Oct 14 2008, at 15:13, John Watlington was caught saying:
>
> I get 898,452 KiB free, on several machines.
> How did you get 921,000 KiB free ?

My bad, accidently used 'df -H' instead of '-h' in my initial check.

So we now have ~878MiB available instead of 822. That's better but that
is still 71Mib (~8%) overhead for the filesystem. 8Mib of that (~1%) is 
reserved for the journal, and the rest is being used for index data 
(as UBI keeps the fs index on-flash which is one way it decreases 
 boot time vs jffs2) or not properly accounted for. I'll keep working
with Artem upstream on understanding the overhead and where we can
tweak it.  One obvious way to do this is to decrease the journal size at 
the expense of some performance as we have to commit more often. There
is also an index fanout option to mkfs.ubifs that I need to understand
a bit better.

~Deepak

-- 
Deepak Saxena - Kernel Developer - dsaxena at laptop.org


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