Ah HA! I b elieve I saw in a dump somewhere that it was 0.9. so I should be off to the races! Thanks! Fred On Wed, Nov 24, 2021 at 1:14 PM Simon Matter <simon.matter at invoca.ch> wrote: > > haven't tried the suggestions yet, but here is some diagnostics on what > > happens when I attempt to mount it: > > upon running *mdadm --assemble /dev/md40 /mnt/dvd --run*, info from > > /var/log/messages): > > (note that /mnt/dvd is just an empty mount point that exists, used here > > for > > convenience). > > > > Nov 24 12:21:42 fcshome kernel: md: md40 stopped. > > Nov 24 12:21:42 fcshome kernel: md/raid1:md40: active with 1 out of 2 > > mirrors > > Nov 24 12:21:42 fcshome kernel: md40: detected capacity change from 0 to > > 996887429120 > > > > output from doing: > > sudo mount /dev/md40 /mnt/dvd > > mount: mount /dev/md40 on /mnt/dvd failed: Structure needs cleaning > > > > corresponding items from /var/log/messages: > > Nov 24 12:22:55 fcshome kernel: XFS (md40): Superblock earlier than > > Version > > 5 has XFS_[PQ]UOTA_{ENFD|CHKD} bits. > > Nov 24 12:22:55 fcshome kernel: XFS (md40): Metadata corruption detected > > at > > xfs_sb_read_verify+0x122/0x160 [xfs], xfs_sb block 0xff > > ffffffffffffff > > Nov 24 12:22:55 fcshome kernel: XFS (md40): Unmount and run xfs_repair > > Nov 24 12:22:55 fcshome kernel: XFS (md40): First 128 bytes of corrupted > > metadata buffer: > > Nov 24 12:22:55 fcshome kernel: ffff8e0c8f4e0000: 58 46 53 42 00 00 10 00 > > 00 00 00 00 0e 81 b1 e0 XFSB............ > > Nov 24 12:22:55 fcshome kernel: ffff8e0c8f4e0010: 00 00 00 00 00 00 00 00 > > 00 00 00 00 00 00 00 00 ................ > > Nov 24 12:22:55 fcshome kernel: ffff8e0c8f4e0020: d2 22 a7 30 dd 88 48 8b > > bd bb 9c 8b 2a 22 72 cc .".0..H.....*"r. > > Nov 24 12:22:55 fcshome kernel: ffff8e0c8f4e0030: 00 00 00 00 08 00 00 04 > > 00 00 00 00 00 00 00 80 ................ > > Nov 24 12:22:55 fcshome kernel: ffff8e0c8f4e0040: 00 00 00 00 00 00 00 81 > > 00 00 00 00 00 00 00 82 ................ > > Nov 24 12:22:55 fcshome kernel: ffff8e0c8f4e0050: 00 00 00 01 00 74 0d 8f > > 00 00 00 20 00 00 00 00 .....t..... .... > > Nov 24 12:22:55 fcshome kernel: ffff8e0c8f4e0060: 00 00 80 00 30 c4 02 00 > > 01 00 00 10 00 00 00 00 ....0........... > > Nov 24 12:22:55 fcshome kernel: ffff8e0c8f4e0070: 00 00 00 00 00 00 00 00 > > 0c 09 08 04 17 00 00 19 ................ > > Nov 24 12:22:55 fcshome kernel: XFS (md40): SB validate failed with error > > -117. > > > > running xfs_repair give: > > sudo xfs_repair /dev/md40 > > Phase 1 - find and verify superblock... > > xfs_repair: V1 inodes unsupported. Please try an older xfsprogs. > > > > before proceeding with other experiments, I decided to use dd to create > an > > image file on my local disk of that partition so I could mess with it > with > > less chance of trashing the on-disk partition. when attempting to use it, > > I > > get: > > > > sudo mdadm --assemble /dev/md41 ./part4.img --run > > mdadm: ./part4.img is not a block device. > > mdadm: ./part4.img has no superblock - assembly aborted > > > > So, I thought maybe the image had somehow become corrupted, so I did: > > > > sudo md5sum /dev/sdd4 > > bd7cac3c886e7b3110e28100e119bb82 /dev/sdd4 > > > > and > > > > md5sum part4.img > > bd7cac3c886e7b3110e28100e119bb82 part4.img > > > > which shows the partition and its disk image to be identical. > > > > Why shouldn't a dd image of a partition work just as well (for my > > purposes) > > as the actual disk partition? I've certainly done this before with EXTn > > and > > NTFS filesystems, is XFS somehow different in this regard? > > > > Do any of you know what I'm doing wrong here? > > I'm not sure but I think you are making it too complicated. > > If the partition is from a software RAID 1, then you should be able to use > it directly without building an mdadm array. > > That said, it depends on the metadata type IIRC. If metadata is in the > beginning of the partition, then you have to remove it by doing a dd to a > file and skipping the metadata in the beginning of the partition. > > md raid metadata locations: > 0.9 At the end of the device > 1.0 At the end of the device > 1.1 At the beginning of the device > 1.2 4K from the beginning of the device > > So with metadata versions 0.9 0r 1.0, you could directly use the md > partition like a normal partition, only some bytes in the end are not used > by the filesystem. > > Regards, > Simon > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos >