[Bug-ddrescue] ddrescue of a ddrescue

[Jonathan Joseph]

I have a failed disk in a failed raid-5 array that I am trying to resurrect with ddrescue.  The disk is 1.5TB, and I successfully did a first pass ddrescue of it (using -f -n flags) to a 2TB drive that I had available (3 errors reported).  Since this is one disk of a raid, there is no proper partition or file system information on it.  You can replace a disk in a raid-5 with a larger one and it will rebuild OK, so I thought the 2TB disk would be fine, but it seems that that just cloning one of the disks of the raid array onto a larger disk will probably not work because in a raid array of this sort, some critical information must be stored at the last block of the disk

The last block of the Anchor DDF Header MUST be the last addressable logical block on a physical disk

So I want the ddrescue copy to go onto an identical 1.5TB drive. I was able to get a matching 1.5TB drive so I would like to do the ddrescue onto that drive now.  However, now that I have already done the ddrescue once, and presumably have most of the data on the 2TB drive.  I want to access the original failed disk as little as possible to prevent making it worse - and hopefully just access the original failed disk to try and improve the error blocks as much as possible.

My question is can I now ddrescue from the 2TB drive to the fresh 1.5TB drive and have everything end up in the right place - including having that  "last block" from the original 1.5TB drive be in the right place on the new 1.5TB drive?  Or do I really need to redo the ddrescue from the original failed 1.5TB disk to the new matching one?

Thanks.

-J