>>>>> "Keld" == Keld Jørn Simonsen <keld@xxxxxxxx> writes: Keld> I have also been thinking a little on this. My idea is that if Keld> bit errors develop on disks, then there is first maybe one bit Keld> error, and the crc check on the disk sectors then finds and Keld> corrects these. Keld> If you rewrite such bit errors, then that bit error will be Keld> corrected, and you prevent the one-bit error from developing to Keld> a two-bit error that is not correctable by the CRC. I think you are assuming that disks are much simpler than they actually are. A modern disk drive protects a 512-byte sector with a pretty strong ECC that's capable of correcting errors up to ~50 bytes. Yes, that's bytes. Also, many drive firmwares will internally keep track of problematic media areas and rewrite or reallocate affected blocks. That includes stuff like rewriting sectors that are susceptible to bleed due to being adjacent to write hot spots. -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
