In the course of trying to recover data from a failing hard drive, I am running the command ddrescue.The command has been running for 9 days, and I thought from the sound of disk activity that maybe it was doing something. The command line output has looked more or less static all this time:$ sudo ddrescue -r3 /dev/sdb /home/dave/RECOVERY/usb500.image /home/dave/recovery_usb500.logfilePress Ctrl-C to interruptInitial status (read from logfile)rescued:         0 B,  errsize:       0 B,  errors:       0Current statusrescued:         0 B,  errsize:    500 GB,  current rate:        0 B/s   ipos:     2539 MB,   errors:       1,    average rate:        0 B/s   opos:     2539 MB,     time from last successful read:     9.7 dSplitting failed blocks... The one part that has been changing is where it says ipos and opos. It took 9 days to get up to around 500000 MB, which is the size of the failing disk drive. When it got there, though, it then dropped back down to 0 and started rising again. As I write this, it's at about 2580 MB and counting.The image file being created is 0 bytes in length.The log file is about 3MB in size and looks like this:# Rescue Logfile. Created by GNU ddrescue version 1.14# Command line: ddrescue -r3 /dev/sdb /home/dave/RECOVERY/usb500.image /home/dave/recovery_usb500.logfile# current_pos  current_status0x975C3000     /#      pos        size  status0x00000000  0x00862000  -0x00862000  0x00014800  /0x00876800  0x00800400  -~~~~~~edited for brevity ~~~~~~~~0x74702CCE00  0x00320000  -0x74705ECE00  0x00025800  /0x7470612600  0x005F3A00  -I'm starting to be concerned that this is just a waste of time and no data is being recovered at all.Is there any indication from this output that anything useful is happening?Is there any reason to let the ddrescue command continue as is, or should I stop it and do something else?This is the most recent contents of /var/log/syslogJun 10 07:29:17 homebase-i3 kernel: [568470.316436] sd 5:0:0:0: [sdb]  Sense Key : Medium Error [current] Jun 10 07:29:17 homebase-i3 kernel: [568470.316443] sd 5:0:0:0: [sdb]  Add. Sense: Unrecovered read errorJun 10 07:29:17 homebase-i3 kernel: [568470.316450] sd 5:0:0:0: [sdb] CDB: Read(10): 28 00 11 ff 02 98 00 00 08 00Jun 10 07:29:17 homebase-i3 kernel: [568470.316465] end_request: critical target error, dev sdb, sector 301925016Jun 10 07:29:17 homebase-i3 kernel: [568470.346640] sd 5:0:0:0: [sdb] Unhandled sense codeJun 10 07:29:17 homebase-i3 kernel: [568470.346646] sd 5:0:0:0: [sdb]  Result: hostbyte=invalid driverbyte=DRIVER_SENSEJun 10 07:29:17 homebase-i3 kernel: [568470.346651] sd 5:0:0:0: [sdb]  Sense Key : Medium Error [current] Jun 10 07:29:17 homebase-i3 kernel: [568470.346656] sd 5:0:0:0: [sdb]  Add. Sense: Unrecovered read errorJun 10 07:29:17 homebase-i3 kernel: [568470.346662] sd 5:0:0:0: [sdb] CDB: Read(10): 28 00 11 ff 02 98 00 00 08 00
Is this ddrescue command doing anything?
hard disk;data recovery;ddrescue