If I get intermittent DMA errors while trying to read a disk, what are my options? FreeBSD's giving me messages like ad4: FAILURE - READ_DMA status=51<READY,DSC,ERROR> error=84 ... before kernel panics.
I don't really understand disk failure modes. My question is primarily: do those happen randomly, in such a way that I can just repeatedly try to copy more data off of the disk and reboot after each panic? Or are they tied to certain sectors, which means I lose some of the data but not all and I just need to be careful which directories to copy? Or am I totally screwed?