Re: Blockbusting news, results get worse

[Pavel Machek]

Hi!

> >>or put it under heavy write workload and remove
> >>power.
> >>
> >Can you tell us more about what really happens to disk drives when the 
> >power is cut while a block is being written?  We engage in a lot of 
> >uninformed speculation, and it would be nice if someone who really knows 
> >told us....
> >
> >Do drives have enough capacitance under normal conditions to finish 
> >writing the block?  Does ECC on the drive detect that the block was bad 
> >and so we don't need to detect it in the FS?
> 
> 
> Does it really matter to speculate about this?
> 
> If you don't FLUSH CACHE, you have no guarantees your data is on the 
> platter.

Well, even without FLUSH CACHE, you can expect that sector being
writen during powerfail either contains old data *or* new data.

If sector can become unreadable after powerfail, I guess journaling
people would like to know, and if powerfail may mean adjacent (or even
unrelated?) sectors to be damaged, everyone needs to know...
								Pavel
-- 
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/