From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Russell Subject: Re: Import/recover RAID6 created with SAS2108? Date: Wed, 9 Mar 2016 15:53:30 -0500 Message-ID: <97E12B93-B712-4FD3-81BE-F60E57B8469B@aol.com> References: <2832CD22-EADC-4BC6-A250-FE8919A92E0A@aol.com> <20160307215026.GA8042@EIS> <20160309192728.GA3581@EIS> Mime-Version: 1.0 (Mac OS X Mail 9.2 \(3112\)) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20160309192728.GA3581@EIS> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Mar 9, 2016, at 2:27 PM, Andreas Klauer wrote: >=20 > On Tue, Mar 08, 2016 at 10:20:17PM -0500, Dan Russell wrote: >> The partially-rebuilt drive is sdk, the original =E2=80=9Cfailed=E2=80= =9D drive is sdag >=20 > Best to leave both out if one has outdated and the other only half=20 > the content=E2=80=A6 I generally agree, but in my case the filesystem wasn=E2=80=99t mounted= (commented out of fstab, movers dropped system, I booted system, RAID = failed before I mounted the filesystem), so I=E2=80=99m OK with the ris= k. >=20 >> However fdisk and mdadm are reporting the array is 17.6TB in size, w= hereas it should be 66TB (24 3TB HDDs RAID6). >=20 > I reproduced your commands using tmpfs based loop devices and it give= s me=20 > the same problem. The RAID size is only 16 TiB. It seems to be hittin= g a=20 > limit somewhere. >=20 > Your /dev/mapper/sdx are snapshot/overlays, I hope? Yes. I can=E2=80=99t recommend highly enough the overlay_setup approac= h on the Wiki. > DDF metadata seems to be located at the end of the device, so you cou= ld try=20 > your luck with mdadm 1.0 metadata instead; that gives me a RAID of a = size=20 > closer to home. This got me closer, but the LVM2 label was missing. When I=E2=80=99d p= reviously assembled the RAID in the container, I noticed algorithm 10; = whereas with this approach it was 2. I switched it to 10 and my array = is back. fsck (xfs_repair -n, really) says the FS is clean and random = poking at files seems to back that up. I have a backup, of course, but doing a disk-to-disk verify/recovery is= going to be so much quicker. Thank you so much for your help, Andreas and all the contributors to th= e =E2=80=9CRAID_Recovery=E2=80=9D and =E2=80=9CRecovering_a_failed_soft= ware_RAID=E2=80=9D Wiki pages. -- 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