On 17-12-17 14:38:02, Chris Murphy wrote: ...
smarctl -l scterc /dev/
This will reveal if this drive supports SCT ERC. If it does, and it's not enabled, it can be set to an obscenely high value, and then a matching SCSI block device command timer might permit deep recovery by the drive's firmware. And then you can just rsync the data from one drive to another. I would not depend on SMB for this.
...
Was it you who told us of a script to cope with drives that don't support SCT ERC?
https://raid.wiki.kernel.org/index.php/Timeout_Mismatch
OP: generally, if a drive can't read a sector in a few seconds, it won't ever be able to read that sector. Possibly more data can be recovered (with some holes) using GNU ddrescue, or the alternative dd_rescue with dd_rhelp. Note that wither would be used to copy a whole partition or disk.
If one has a backup, using rsync and getting the failed files from the backup is probably faster than using either dd*rescue.