I'm trying to recover a partition on a bad drive with ddrescue. I run:
$ sudo ddrescue -r -1 -v /dev/sdd3 OUT.img dd_rescue_logfile
and it seems to do great for a while, but after about an hour, the "current rate" drops to zero because the drive disappeared from /dev. To bring the drive back, the only thing I can think of is to reboot the system and run the ddrescue command to resume from where I left off. This makes it very difficult to run the program, as I can't just leave it and forget it for a few days - I have to constantly monitor it to make sure the disk didn't disappear. I have seen this behavior on both Arch linux, and Fedora 22.
I assume that at some point, the kernel has trouble accessing the drive and removes it from /dev. Is there any way to avoid this? To tell the kernel to keep the device there even if it looks like it's broken or non-existent?