On 8 Feb 2016 01:25 +0100, from sven@xxxxxxxxxxxxxxxxxxxxx (Sven Eschenberg): > I always > wondered how a HDD exactly behaves when power fails, while a sector > is in transit. My best hope is, that the CRC at the end of the > sector does not match and an error is returned on the next read? That's the theory; if a sector write is interrupted half way through (regardless of the reason), then the FEC data doesn't match the sector payload data. In this case, the difference is very likely large enough that the error cannot be corrected using the FEC data, so you get a read error back instead. _Unfortunately_, theory and practice don't always agree. I think it was Google that did a study on storage errors not all that long ago, and one conclusion was that silent read errors (where you do get data back from the drive, but that data is not the same as was originally written), while rare, happens with a high enough probability to warrant consideration in large storage systems. -- Michael Kjörling • https://michael.kjorling.se • michael@xxxxxxxxxxx “People who think they know everything really annoy those of us who know we don’t.” (Bjarne Stroustrup) _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
