RAID 5 build time optimization question and experiments.

Quoted 9 lines

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->

Quoted 4 lines

The create worked fine and I waited for the rebuild to be complete before stopping the array and dumping the SBs.

Quoted 3 lines

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        <[email protected]> |
 / / )      | Little Jim says ....                            | // !!       |      "He fallen in de water !!"                 |

Quoted 15 lines · Cat'Killer

Quoted 9 lines

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->

Quoted 4 lines

The create worked fine and I waited for the rebuild to be complete before stopping the array and dumping the SBs.

Quoted 7 lines

Quoted 3 lines

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.

Thank you for this, that's exactly what I was looking for. I had looked in the manpage beforehand but I did not search for the right terms nor assumed this would work in case of an array created ontop of zeroed drives.

Thanks again.

Ben.

Quoted 11 lines

Cheers,
  Robin

--
   ___           ( ' }     |       Robin Hill        <[email protected]> |
 / / )      | Little Jim says ....                            | // !!       |      "He fallen in de water !!"                 |

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