Mailinglist Archive: opensuse (1473 mails)

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Re: [opensuse] dmraid disk failure - howto rebuild new disk - gparted hates Me :-(
  • From: Greg Freemyer <greg.freemyer@xxxxxxxxx>
  • Date: Sat, 13 Jun 2009 09:23:39 -0400
  • Message-id: <87f94c370906130623l403e3766hf421f2533ddaed70@xxxxxxxxxxxxxx>
On Sat, Jun 13, 2009 at 2:34 AM, David C.
Rankin<drankinatty@xxxxxxxxxxxxxxxxxx> wrote:
David C. Rankin wrote:

      My Seagate drives are dropping like flies with less than 1400 hours of
time. (that's less than 58 days of service!)
      That's pretty much where I am now. My next thought is to just use dd
to copy
the partitions over. I have opensuse on the sda/sdc array (mapper
nvidia_fdaacfde), so the drives I am working with are not mounted anywhere
should be easy to work with.

      What says the brain trust? Can you think of any way I was screwing up
so it wouldn't even format the copy partitions? What about the dd method? Any
hints or gotchas? Any help would be appreciated. Thanks.

Here is what I'm going with:

       dd bs=100M conv=notrunc if=/dev/sdb of=/dev/sdd

We shall see if it works...

David C. Rankin, J.D.,P.E.


I did not read your first post with issue, but the above dd command is
almost certainly wrong, but you won't have an issue unless you have an
i/o error.

You need to use "conv=noerror,sync" and you want the block size to be 4k.

I believe notrunk will fill the remainder of the disk with zeros after
the first error. Very bad. Think about a single media error early in
the drive.

"noerror, sync" will fill the current block with zeros. So with a 4k
block you are doing the best kernel can provide (at least via dd.)
ie. the kernel itself uses 4k blocks.

With a 100M block, if you have a i/o error you are going to blast a
huge hole in the middle of your data.

Greg Freemyer
Head of EDD Tape Extraction and Processing team
Litigation Triage Solutions Specialist
First 99 Days Litigation White Paper -

The Norcross Group
The Intersection of Evidence & Technology
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