PYTHONPATH=$PWD nbdkit -f --filter=blocksize python nbd.py ip=192.168.1.105

 nbd-client 127.0.0.1 10809

$ ddrescue /dev/nbd0 pb8088rescue.raw pb8088rescue.nfo
GNU ddrescue 1.26
Press Ctrl-C to interrupt
     ipos:   42205 kB, non-trimmed:    2336 kB,  current rate:   21845 B/s
     opos:   42205 kB, non-scraped:        0 B,  average rate:   17365 B/s
non-tried:   12518 kB,  bad-sector:        0 B,    error rate:       0 B/s
  rescued:   27364 kB,   bad areas:        0,        run time:     26m 15s
pct rescued:   64.81%, read errors:       59,  remaining time:         10m
                              time since last successful read:          0s
Copying non-tried blocks... Pass 1 (forwards)
     ipos:    65536 B, non-trimmed:    3621 kB,  current rate:    5006 B/s
     opos:    65536 B, non-scraped:        0 B,  average rate:   15878 B/s
non-tried:    6619 kB,  bad-sector:      512 B,    error rate:    2275 B/s
  rescued:   31978 kB,   bad areas:        1,        run time:     33m 34s
pct rescued:   75.74%, read errors:       93,  remaining time:         18m
                              time since last successful read:          0s
Copying non-tried blocks... Pass 2 (backwards)
     ipos:   196608 B, non-trimmed:    4268 kB,  current rate:       0 B/s
     opos:   196608 B, non-scraped:        0 B,  average rate:   15468 B/s
non-tried:    3145 kB,  bad-sector:      512 B,    error rate:   32768 B/s
  rescued:   34804 kB,   bad areas:        1,        run time:     37m 30s
pct rescued:   82.43%, read errors:      110,  remaining time:          9m
                              time since last successful read:          2s
Copying non-tried blocks... Pass 4 (backwards)
     ipos:   14417 kB, non-trimmed:    5460 kB,  current rate:   21845 B/s
     opos:   14417 kB, non-scraped:        0 B,  average rate:   14750 B/s
non-tried:        0 B,  bad-sector:      512 B,    error rate:       0 B/s
  rescued:   36758 kB,   bad areas:        1,        run time:     41m 32s
pct rescued:   87.06%, read errors:      138,  remaining time:          6m
                              time since last successful read:          0s
Copying non-tried blocks... Pass 5 (forwards) 
     ipos:   26082 kB, non-trimmed:        0 B,  current rate:   20480 B/s
     opos:   26082 kB, non-scraped:   990208 B,  average rate:   13730 B/s
non-tried:        0 B,  bad-sector:    62976 B,    error rate:       0 B/s
  rescued:   41166 kB,   bad areas:      123,        run time:     49m 57s
pct rescued:   97.50%, read errors:      260,  remaining time:         54s
                              time since last successful read:          0s
Trimming failed blocks... (forwards)         
     ipos:   14658 kB, non-trimmed:        0 B,  current rate:    9216 B/s
     opos:   14658 kB, non-scraped:        0 B,  average rate:    8450 B/s
non-tried:        0 B,  bad-sector:   499712 B,    error rate:       0 B/s
  rescued:   41719 kB,   bad areas:      138,        run time:  1h 22m 16s
pct rescued:   98.81%, read errors:     1113,  remaining time:          0s
                              time since last successful read:         n/a
Scraping failed blocks... (forwards)
Finished