Re: ddrescue reports Finished before disk writing is complete.

[Eric Lovejoy]

My bad, I didnt include the ddrescue version.
I have encountered this issue in version 1.23, and version 1.26
$ sudo ddrescue --version
GNU ddrescue 1.26
Copyright (C) 2022 Antonio Diaz Diaz.
License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html
>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

On Tue, Jan 10, 2023 at 2:43 PM Eric Lovejoy <blicken@gmail.com> wrote:

> So then you get impossibly fast write times, and boot disks that dont
> work, because they arent actually complete, if the user removes the disk
> when ddrescue reports that the operation is complete.
>
> $ sudo ddrescue --force bodhi-6.0.0-64.iso /dev/sdb
> GNU ddrescue 1.23
> Press Ctrl-C to interrupt
>      ipos:  872349 kB, non-trimmed:        0 B,  current rate:    727 MB/s
>      opos:  872349 kB, non-scraped:        0 B,  average rate:    436 MB/s
> non-tried:        0 B,  bad-sector:        0 B,    error rate:       0 B/s
>   rescued:  872415 kB,   bad areas:        0,        run time:          1s
> pct rescued:  100.00%, read errors:        0,  remaining time:         n/a
>                               time since last successful read:         n/a
> Finished
>
>
> Shown here, a 1 second run time, for a 700MB file to USB. But I already
> know this is impossible on my hardware. I'm just a dumb construction
> worker, but if i had to guess, ddrescue is listening to userspace
> libraries, rather than kernel signal processes.
>
> Here iostat reports:
> iostat -d
> Linux 5.15.0-56-generic (i) 01/10/2023 _x86_64_ (12 CPU)
>
> Device             tps    kB_read/s    kB_wrtn/s    kB_dscd/s    kB_read
>  kB_wrtn    kB_dscd
> loop0             0.01         0.09         0.00         0.00       1133
>        0          0
> loop1             0.01         0.09         0.00         0.00       1133
>        0          0
> loop2             0.00         0.03         0.00         0.00        363
>        0          0
> loop3             0.01         0.09         0.00         0.00       1090
>        0          0
> loop4             0.01         0.04         0.00         0.00        439
>        0          0
> loop5             0.01         0.04         0.00         0.00        438
>        0          0
> sda              47.56       465.18       313.64         0.00    5574816
>  3758761          0
> sdb               0.47         0.16        36.52         0.00       1932
>   437704          0
>
> It appears from iostat, that the disk sdb is still being written, despite
> ddrescue reporting completion.
>
>