gmirror: replacing failed disks

Christian Hiris 4711 at
Wed Jan 19 17:04:13 PST 2005

Hash: SHA1

On Wednesday 19 January 2005 22:53, you wrote:
> On Wed, Jan 19, 2005 at 06:55:53AM +0100, Christian Hiris wrote:


> >
> > 2.2. Blank out gmirror metadata on ad4
> >      # dd if=/dev/zero of=/dev/ad4 bs=512 skip=156301400
> This command took "a long time" and I didn't let it complete.  I use the
> tcsh and would occassionaly hit <ctrl> T to track it's progress.  I
> didn't see it writing data to the disk nor did I see disk activity.  Did
> I not wait long enough?

Ooops, I just realized that option 'skip=n' skips the blocks on the *input* 
file. The correct option to "skip" blocks on the outfile is 'seek=n'. It 
didn't damage anything in our case, but it waisted your time. Sorry about 
this  mistaken option and the time you lost from this. The command's only 
purpose is to re-design the drive, as if it hasn't ever faced the gmirror 
framework before. 
Just for the archives the corrected (and double-checked) command: 

   2.2. Blank out gmirror metadata on ad4
        # dd if=/dev/zero of=/dev/ad4 bs=512 seek=n
        where n=(metadata_location_in_bytes/512)-1


> Christian,
> Other than the issue with 2.2 above, the procedure worked and the
> "replacement" drive is now synchronizing.  Now I'll print out a
> transcript of this and tape it to the box,  Then, in three years, when a
> drive dies, I'll remember what to do :)
> Thanks again for all your help.

Just in case, if the tape fails :)

It's excellent!

Good luck,

- -- 
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