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I have an old disk that often gets stuck in some form of loop, and often I need to perform a full reboot to get it "unstuck", whereupon I had found out about the hdparm -w command. However, its manpage lists this command as dangerous:


Perform a device reset (DANGEROUS). Do NOT use this option. It exists for unlikely situations where a reboot might otherwise be required to get a confused drive back into a useable state.

What are the dangers, and do they exceed the dangers of data loss due to a hard-reboot?

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The dangers of hdparm -w aside, if your drive requires extra measures of any kind, the only thing left to do is to back up the data and replace the drive. Non-negotiable. –  DevSolar Jul 20 '12 at 15:01
@DevSolar It's an old drive being mounted as /tmp and I am too cheap to get a drive right now... –  hexafraction Jul 20 '12 at 15:03
Even if it is "only" /tmp, a storage device that does not work flawlessly always poses imminent danger of irrecoverable data loss. If that doesn't bother you, use hdparm -w and don't worry because dangers obviously don't matter. If you do care for your data, replace the drive. –  DevSolar Jul 20 '12 at 15:07
OK. I still would like to know about the command's dangers. –  hexafraction Jul 20 '12 at 15:10
I assume much of the danger implied by the hdparm man page arises from file systems not properly unmounted, certain drive's firmware not responding to a soft reset properly etc.; as I said, if you don't give a damn, go right ahead. ;-) –  DevSolar Jul 20 '12 at 15:10

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