jffs2: too few erase blocks

Jamie Lokier jamie at shareable.org
Thu Oct 25 18:15:53 EDT 2007

Josh Boyer wrote:
> > Hi All,
> > What's the deal with "too few erase blocks" message?
> > Is one block too few for a jffs2 partition?
> > My block size if 256K and I created a small jffs2 256K partition for
> > read/writing.
> > Is this really too small for jffs2? If so, is there anything I can do for this?
> Yes, it's too small.  JFFS2 requires a certain percentage of blocks in
> the partition to be reserved for it's usage.  At one point, it was 5
> eraseblocks.

Fwiw, 5 blocks worth of free space is no guarantee that it'll be fine.
I have a 1MB JFFS2 partition with 64kB eraseblocks.  That's 320kB in 5
blocks.  But it can return disk full errors when reporting more than
320kB free with 'df' (somewhere between 5 and 6 blocks worth), and it
can also do strange things shortly before it returns disk full errors,
like spending lots of CPU on GC.

-- Jamie

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