How to use a second source disk for a second pass with ddrescue

[King Marzo]

Hi,

I'm trying to use ddrescue to recover the data from a Linux raid 1 where both 
disks have errors. I ran ddrescue to get the data from the first disk onto a 
new disk, but I'm not sure how to run it on the second disk, and I've scoured 
the Internet for two days now and can't find what command I actually need to 
run to do this. I thought all I needed to do was to run the exact same command 
as I did for the first disk but just change the source drive to the second disk.

I first ran: sudo ddrescue -f -n /dev/sdb1 /dev/sdd /root/recovery.log
Once that had completed, I ran: sudo ddrescue -f -n /dev/sdc1 /dev/sdd 
/root/recovery.log

Note that all I did was change the source drive from sdb1 to sdc1, but the 
second pass instantly completes with the exact same summary as the first pass, 
so I get the impression that it didn't do anything at all...but maybe I'm not 
doing it right?

Sorry if this is not the right place to ask questions about this, but I 
couldn't find any forum for this or IRC channel or anything, and the gnu page 
for ddrescue did say to write to this email address for help, so I hope it was 
alright to email this address. Or if not, do you know of a better place that I 
could ask this question? Thanks!

Sincerely,

David