Re: failing HDD, ddrescue says remaning time is 7104d
On Wed 31 Aug 2022 at 16:33:39 (-0700), David Christensen wrote:
> On 8/31/22 15:35, David Wright wrote:
> > On Wed 31 Aug 2022 at 14:02:19 (-0700), David Christensen wrote:
> > > On 8/31/22 06:25, ppr wrote:
> > > > I would appreciate advice from the community about a failing hard drive.
> > > >
> > > > When booting up, the computer complained about /dev/sdb, which is
> > > > a ext4 HDD with data (not the computer main disk). dmesg shows
> > > > `AE_NOT_FOUND` and `failed command: READ FPDMA QUEUED` messages
> > > > (full dmesg log at https://hastebin.com/raw/jebelileru).
> > > >
> > > > It has finally booted after trying unsuccessfully to start /dev/sdb.
> >
> > > Comment out the /etc/crypttab and/or /etc/fstab entries for the failed
> > > drive. When you mount the drive, mount it read only.
> >
> > I don't think it's wise to mount this disk at all, and certainly not
> > before everything that can be rescued from it has been obtained and
> > copied/archived.
>
> First sentence -- You don't want the OS to access the drive on the
> next boot.
>
> Second sentence -- I should have prefaced that with "after ddrescue
> has finished".
Yes, I was misled by the order of paragraphs.
> > > Consider doing the work in chunks. You
> > > should already have sectors 0- 33 GB. Skip 33 GB and/or 34 GB. Do
> > > 35-100 GB. Then, 100-200 GB, 200-300 GB, 300-400 GB, etc.. Get the
> > > good sectors first. Do the problem sectors last.
> >
> > Agreed, though ddrescue should be able to do this more flexibly, and
> > automatically, with -K.
>
> RTFM [1], I don't know if I would use -K. Take a look at the examples
> given at the end of section "4 Algorithm" and in "10 A small tutorial
> with examples" (examples 3 and 5 look relevant to the OP).
I guess it would be worth setting -a --min-read-rate in addition,
as 636 bytes/sec is unsustainable. This will trigger the skipping.
But the most help could be just reversing the pass, to see whether
the "damage" is local or across the whole disk.
As for the examples, I didn't see a freeze reported (ex.3), nor any
read errors (ex.5), just a slowdown; I think ex.3 is for occasions
when reading particular sectors just locks up the disk.
Cheers,
David.
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