[CentOS] Using CentOS 7 to attempt recovery of failed disk

Sun Sep 27 16:27:40 UTC 2020
Erick Perez - Quadrian Enterprises <eperez at quadrianweb.com>

@tonymountifield
Does this still hold true?
https://superuser.com/a/1075837


On Sun, Sep 27, 2020 at 7:21 AM Tony Mountifield <tony at softins.co.uk> wrote:

> In article <E02FA554-9D6D-4E7D-8A78-5FBDE1DE939D at kicp.uchicago.edu>,
> Valeri Galtsev <galtsev at kicp.uchicago.edu> wrote:
> >
> >
> > > On Sep 26, 2020, at 8:05 AM, Jerry Geis <jerry.geis at gmail.com> wrote:
> > >
> > > I have a disk that is flagging errors, attempting to rescue the data.
> > >
> > > I tried dd first - if gets about 117G of 320G disk and stops
> incrementing
> > > the save image any more.
> >
> > did you try
> >
> > dd conv=noerror …
> >
> > this flag makes dd not stop on input error. Whatever is irrecoverable is
> irrecoverable, but this way you will get stuff
> > beyond failure point.
>
> You need conv=noerror,sync so that unreadable sectors get replaced by
> zeros instead of not being written out at all.
> Without sync, the filesystem geometry on the destination image will be
> wrong after the first error.
>
> You also need bs=4096 so that ONLY the bad sector(s) get zeroed, and not
> the surrounding ones. If you have, say,
> bs=1M, then you will get a megabyte of zeros if any block within that
> megabyte is bad.
>
> I'm speaking from recent experience!
>
> Cheers
> Tony
>
> --
> Tony Mountifield
> Work: tony at softins.co.uk - http://www.softins.co.uk
> Play: tony at mountifield.org - http://tony.mountifield.org
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>


-- 

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Erick Perez
Quadrian Enterprises S.A. - Panama, Republica de Panama
Skype chat: eaperezh
WhatsApp IM: +507-6675-5083
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