From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Cat'Killer" Subject: Re: RAID 5 build time optimization question and experiments. Date: Fri, 11 Dec 2009 16:57:39 +0000 Message-ID: References: <4B227932.80503@mpstor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <4B227932.80503@mpstor.com> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids > 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 hour= s! >> >> Once done, I then created a RAID 5 on 10 disks, waited for the rebui= ld >> 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 v= ery > little time at all. =A0If 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, > =A0 Robin > > -- > =A0 =A0___ =A0 =A0 =A0 =A0 =A0 ( ' } =A0 =A0 | =A0 =A0 =A0 Robin Hill= =A0 =A0 =A0 =A0 > | > =A0/ / ) =A0 =A0 =A0| Little Jim says .... =A0 =A0 =A0 =A0 =A0 =A0 =A0= =A0 =A0 =A0 =A0 =A0 =A0 =A0| > =A0// !! =A0 =A0 =A0 | =A0 =A0 =A0"He fallen in de water !!" =A0 =A0 = =A0 =A0 =A0 =A0 =A0 =A0 | > > > -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html