Greg Oster <oster@cs.usask.ca> writes:

> There are some serious consequences to doing *ANYTHING* to data on a
> RAID set before the parity rewrite completes.  If the parity is not
> correct for a given stripe, and you write real data to a portion of
> that stripe, old (and *incorrect*) parity will be used to create the
> new parity, and that new parity will also be *incorrect*.

Shouldn't the correct parity be calculated on demand then? That is,
fix the parity of the stripes you write to, before you write to them.

/Johan