Re: RAID 5 build time optimization question and experiments.

[Robin Hill <robin@robinhill.me.uk>]

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On Fri Dec 11, 2009 at 02:55:31PM +0000, Cat'Killer wrote:

> I found a way using Doug Gilbert's great sg3utils to zero all these
> disks in a very efficient manner, using sgp_dd, at near drive
> bandwidth, and proceeded to zero all the disks fully in about 4 hours!
> 
> Once done, I then created a RAID 5 on 10 disks, waited for the rebuild
> to complete, stopped the array using mdadm, and dumped each of the
> RAID's components superblocks to files.
> 
<-snip->
> The create worked fine and I waited for the rebuild to be complete
> before stopping the array and dumping the SBs.
> 
> I then proceeded to write these same superblocks to 10 new similar
> disks in a different system.
>
You could just do the create with --assume-clean, which should take very
little time at all.  If the drives were zeroed initially then this will
give you valid parity data.

Cheers,
    Robin

-- 
     ___        
    ( ' }     |       Robin Hill        <robin@robinhill.me.uk> |
   / / )      | Little Jim says ....                            |
  // !!       |      "He fallen in de water !!"                 |

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