Re: RAID 5 build time optimization question and experiments.

["Cat'Killer" <catkiller@gmail.com>]

> 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.
>
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.

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