Chiming in with some additional information that only *partially* contradicts certain things that have been said in this thread. First off though, the advice that drives are cheap and data is expensive is absolutely correct. Do NOT let anything I say talk you out of making sure any critical data on this drive is backed up. Given that tee-up, smartctl/smartd reports that the disk has an "uncorrectable bad sector" when there is a read error from the drive for a sector. The error is "uncorrectable" because the sector cannot be read. Note that the detection of a bad read (or write) takes place at the physical and drive firmware level when the CRC is checked. The only thing that the drive has to work with is that there was an attempt to read a sector and that read resulted in a CRC error. The bad sector is part of a file and only you, the user, can make a determination as to whether the rest of the file is still good or if the bad sector is throwing a CRC error but the file is still usable. That's also why the error is "uncorrctable". The drive doesn't have enough information to fix it and it can't silently remap the sector since it can't read the data. If it did, you would end up with a file with a null sector somewhere in it at the location that corresponds to the bad sector's data. Write errors the drive takes care of through the reallocation process mentioned earlier in the thread (since data is being written, any existing data is being replaced so the data can be written to a remapped sector). Read errors the drive can only report the problem since the read error implies that data cannot be retrieved. My advice: buy a new drive but run badblocks -w on the old drive once you have your data safely off of it. You will probably find that the badbloocks write test (-w) lets the drive see the bad sector being written to and then remaps the bad sector and you end up with a drive that is now completely usable again. Be absolutely sure you have your data off of the drive before running badblocks -w. It will overwrite any data on the drive. I have "recovered" several drives by doing this. I've also had some that threw errors all over the place. Those became targets. Cheers, Dave -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines Have a question? Ask away: http://ask.fedoraproject.org
