If I'm remembering correctly, the 0.9 and 1.2 superblocks are both at the end of the partitions, so is it possible to do it by shrinking the raid a bit then stopping it and forcing creation of a new raid with exactly the same parameters (save for the superblock format) and telling it not to rebuild?
Which all sounds rather scary...
Also, is there a way to tell md to save more room for the superblock stuff (like the bad block lists or the bitmap)?
Which leads to the next question... is there a "good" size for the bitmap? I like what it does for me, so I assume a larger bitmap would lead to more granular information. So on a massive raid, having more pages might be better.
Thanks, as always.