On Sun, Jun 26, 2016 at 06:18:04PM -0400, Phil Turmel wrote: > I don't know *any* scenario where dd is useful for raid recovery. Basically you use dd to make a copy to play around with but with overlays (as described in the RAID wiki) you don't need those copies anymore. [as long as the device is intact] There is conv=noerror,sync however I found recently that it actually produces corrupt copies (changes offsets), still not sure what the conv=noerror,sync is actually supposed to be for. ( http://superuser.com/a/1075837/195171 ) So you shouldn't use dd on bad disks... I've had my fair share of issues with ddrescue as well, it likes to get stuck forever and not continue. --min-read-rate=<bytes> might help in such a case... (better to copy regions that still work quickly rather than spending hours on error correction ...). ddrescue produces a log (or a map) that records bad regions, so if you somehow need a device that still produces read errors for those, it can probably be magicked with the device mapper... Regards Andreas Klauer -- 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
