Paranoid read mode for raid5/6

Paranoid read mode for raid5/6

[Mattias Wadenstein]

Hi *,

Is there way to tell md to be paranoid and verify the parity for raid5/6 
on every read? I guess this would come with a (significant) performance 
hit, but sometimes that's not a big deal (unlike disks scrambling your 
data).

Also, regarding data paranoia, for check/repair of a raid6, is the effort 
made to figure out which is the misbehaving participant device, or is 
parity just blindly recalculated?

/Mattias Wadenstein

Re: Paranoid read mode for raid5/6

[Dan Williams]

On 6/11/07, Mattias Wadenstein <maswan@acc.umu.se> wrote:
> Hi *,
>
> Is there way to tell md to be paranoid and verify the parity for raid5/6
> on every read? I guess this would come with a (significant) performance
> hit, but sometimes that's not a big deal (unlike disks scrambling your
> data).
>
> Also, regarding data paranoia, for check/repair of a raid6, is the effort
> made to figure out which is the misbehaving participant device, or is
> parity just blindly recalculated?
>
This is something that is not available today, but is something I am
looking to implement.  Especially for the raid6 case where hpa showed
that not only can corruption be detected, it can be corrected.

> /Mattias Wadenstein

Dan