From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: RAID 5 rebuild fails with power interruption. Date: Tue, 17 Nov 2009 09:47:20 +1100 Message-ID: <20091117094720.4c8736d7@notabene.brown> References: <8338BD137FF1B64EB341218BD702985E02AB8FCF@BLR-EC-MBX03.wipro.com> <87y6m759o2.fsf@frosties.localdomain> <8338BD137FF1B64EB341218BD702985E02AB90B8@BLR-EC-MBX03.wipro.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <8338BD137FF1B64EB341218BD702985E02AB90B8@BLR-EC-MBX03.wipro.com> Sender: linux-raid-owner@vger.kernel.org To: senthilkumar.muthukalai@wipro.com Cc: goswin-v-b@web.de, linux-raid@vger.kernel.org List-Id: linux-raid.ids On Mon, 16 Nov 2009 16:00:38 +0530 wrote: > We face this problem in our NAS product where we handle RAID5. > In the below mentioned scenario, when RAID5 is rebuilding after > adding a disk, we reset the power. > Ideally when the system comes up, the RAID5 should have accepted the > disk but not in our case. > We get the 'kicking the non-fresh disk from array' message with the > boot message. > In our RAID init script we run 'mdadm -- Examine -- scan', followed by > 'mdadm --assemble'. > Could you pls help me to understand why this disk is being thrown out? It is because the metadata being used (v0.90) does not have the ability to record that a device is partially recoverred. It can only record that a device is either a full member of the array, or is not a member of the array. So until the recovery completes, the metadata only records that the device is not a member of the array. So when you restart, you find that the device is not a member of the array. > What could be the solution? Use 1.x metadata. e.g. add --metadata=1.1 to your --create command. 1.x metadata is able to record that a device is only partially recovered. So when the array is restarted the device will be included and recovery will continue. NeilBrown > > -----Original Message----- > From: goswin-v-b@web.de [mailto:goswin-v-b@web.de] > Sent: Monday, November 16, 2009 10:49 AM > To: SenthilKumar Muthukalai (WT01 - Telecom Equipment) > Cc: linux-raid@vger.kernel.org > Subject: Re: RAID 5 rebuild fails with power interruption. > > writes: > > > Adding a subject line... > > > > -----Original Message----- > > From: SenthilKumar Muthukalai (WT01 - Telecom Equipment) > > Sent: Monday, November 16, 2009 9:14 AM > > To: linux-raid@vger.kernel.org > > Subject: > > > > Hi All, > > > > Could you pls help me out with the below problem? > > > > 1. Created a RAID5 with 3 disks. > > 2. Initial rebuild done. > > 3. Pulled out a disk from the array. > > 4. The array got degraded. > > 5. Added the disk back to the array with 'assemble' command. > > 6. The disk was successfully added and the array started rebuilding > > again. > > 7. While rebuilding, reset the power to the NAS box. > > 8. When the NAS box boot up, the RAID was in degraded with the added > > disk thrown out. > > 9. The boot messages say 'kicking out of the non-fresh disk from the > > array'. > > > > We tried '--force' option with the 'assemble' command but no > > success. > > > > Thanks, > > Senthil M > > mdadm --add /dev/md0 /dev/sdc1 > > But normaly it should just continue the resync. > > MfG > Goswin > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" > in the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html