Re: modifying degraded raid 1 then re-adding other members is bad

From: Neil Brown
Date: Wed Aug 09 2006 - 19:17:17 EST


On Wednesday August 9, jengelh@xxxxxxxxxxxxxxx wrote:
> >> Why we're updating it BACKWARD in the first place?
> >
> >To avoid writing to spares when it isn't needed - some people want
> >their spare drives to go to sleep.
>
> That sounds a little dangerous. What if it decrements below 0?

It cannot.
md decrements the event count only on a dirty->clean transition, and
only if it had previously incremented the count on a clean->dirty
transition. So it can never go below what it was when the array was
assembled.

NeilBrown
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