Hi, love the awesome job on ddrescue. I had a question that I have been unable to figure out/sufficiently test. I work in PC Repair and we do quite a bit of data rescue. With that said, we have noticed random spikes in NTFS-3g processor usage when utilizing an NTFS drive as a repository for the images. We have actually been noticing this for a while, but only recently pegged it to NTFS-3g. I looked on their support page, and they mention block size and sparse writes being issues when using dd, so I assume similar issues here. We did use ext3 as a storage volume for the images, and noticed a marked improvement.
With that all said, I know there would be issues in doing data recovery with large block sizes (higher rate of missing data, etc.), but I am wondering if the asynchronous switch would be able to help with this, or perhaps a quick run through with a large block size, no trim, etc, then a second pass with a smaller one.
Just wondering what type of thoughts you have on this. Thanks for your help and keep up the great work!