Hi, I have a failing 12TB disk and I have been able to image all but about 140GB of it by using the -a option to keep the read rate reasonable. The remaining skipped blocks also appear to be readable, but only at a very low rate (retries with successively lower -a values as well as the reported read rates indicate ~30 KB/s). As it will take a few months to recover the remaining data at this rate, I am hunting for a way to speed up the process. I did not use the -d option in any of my prior attempts and I wonder if this may increase the read rate? I am slightly afraid to try this option, however, since I am worried that it may not be compatible with my current map file. So a few questions:
1. Can I add the -d (and -b) options on subsequent reruns? 2. If so, will it help? 3. Is there any other way to speed up reading these stubborn blocks? I am not sure if this is kosher, but I have been editing the map file so that the current position points to the start of the first non-tried or non-trimmed block and then using commands like ddrescue -R -a 50k --cpass=1,2 -n -N -f /dev/sdb /dev/sdc map.out Without editing the map file, I found that ddrescue would often start at either pass 3 or 4 even when I used the --cpass option (thereby ignoring the -a input). I am sure there is a better way to cause ddrescue to start over with passes 1 and 2 (I tried -r 2 but to no avail). Perhaps someone can enlighten me on this. Also note that I am not attempting to trim or scrape, as I will do that at the very end. Currently I have only ~180KB marked as being non-trimmed. -- Thomas Lund, Ph.D. Global Atmospheric Technologies and Sciences, Inc 3360 Mitchell Ln Boulder, CO 80301