[Beowulf] HD undetectable errors

Henning Fehrmann henning.fehrmann at aei.mpg.de
Mon Aug 24 01:58:56 PDT 2009


Hello Peter,

Thank you for the answer.

> 
> Yes. But most wont and it will hur quite a lot performance wise. I know, for 
> example, that our IBM DS4700 with updated firmware can 
> enable "verify-on-read".

Is it easily possible to switch this feature on and off?
E.g., one does a a test from time to time but for the every day usage
one avoids "verify-on-read"?

> Remember that you have to calculate this against the amount of corrupt data, 
> not the total amount of data.

My hope is that corrupted data will be repaired by the RAID controller. The
chance to loose the data on a RAID6 system is of the third order should be very small.
My guess it that the silent corruption rate is higher if the RAID
system does not have the "verify-on-read" feature. I try to get the numbers. 
I assume in this calculation that no bit flips occur on the buses or
the controller which is already sort of naive.

Thank you.

Cheers,
Henning



More information about the Beowulf mailing list