I've noticed a regression in IMSM metadata support in v3.5-rc kernels. I have a two-disk laptop that I run an IMSM RAID0 on so I can dual-boot Windows: :; sudo mdadm --detail-platform Platform : Intel(R) Matrix Storage Manager Version : 8.0.0.1039 RAID Levels : raid0 raid1 Chunk Sizes : 4k 8k 16k 32k 64k 128k 2TB volumes : not supported 2TB disks : not supported Max Disks : 4 Max Volumes : 2 per array, 2 per controller I/O Controller : /sys/devices/pci0000:00/0000:00:1f.2 (SATA) :; cat /proc/mdstat Personalities : [raid0] md126 : active raid0 sda[1] sdb[0] 625137664 blocks super external:/md127/0 128k chunks md127 : inactive sdb[1](S) sda[0](S) 4520 blocks super external:imsm unused devices: <none> What's happened in v3.5 is that it's no longer possible to incrementally assemble this array, as for example udev rules do. This breaks my initramfs, and I wind up at a recovery prompt. 'mdadm --assemble --scan' is still able to bring up the array enough to get lvm going, though I think it's still a little messed up; note the 0 length metadata partition reported here: :; cat mdstat.bad Personalities : [raid0] md126 : active raid0 sda[1] sdb[0] 625137664 blocks super external:/md127/0 128k chunks md127 : inactive sdb[1](S) sda[0](S) 0 blocks super external:imsm unused devices: <none> Manually running the incremental mdadm looks like this: # mdadm -I /dev/sda [ 22.514509] md: bind<sda> mdadm: failed to add /dev/sda to /dev/md/imsm0: Invalid argument. [ 22.516151] md: md127 stopped. [ 22.516234] md: unbind<sda> [ 22.536399] md: export_rdev(sda) The same "mdadm: ... Invalid argument." messages print out from the --assemble --scan, yet the array comes up (enough to mount, anyway). I bisected down to this commit: commit c6563a8c38fde3c1c7fc925a10bde3ca20799301 Author: NeilBrown <neilb@xxxxxxx> Date: Mon May 21 09:27:00 2012 +1000 md: add possibility to change data-offset for devices. Heres the relevant dmesg sections for the good and bad case. Please let me know if there's anything else I can provide to help fix this. Good dmesg: [ 0.000000] Linux version 3.4.0-rc5-ARCH-00006-g2c810cd (bdowning@saphira) (gcc version 4.7.1 (GCC) ) #16 SMP PREEMPT Tue Jul 17 03:19:00 CDT 2012 [ 0.000000] Command line: root=UUID=89ccd806-db3e-49d2-a338-5efb0c5829dc ro initrd=../initramfs-linux-git.img BOOT_IMAGE=../vmlinuz-linux-git ... [ 2.311681] sd 0:0:0:0: [sda] 625142448 512-byte logical blocks: (320 GB/298 GiB) [ 2.311686] sd 4:0:0:0: [sdb] 625142448 512-byte logical blocks: (320 GB/298 GiB) [ 2.311775] sd 4:0:0:0: [sdb] Write Protect is off [ 2.311777] sd 4:0:0:0: [sdb] Mode Sense: 00 3a 00 00 [ 2.311814] sd 4:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [ 2.312150] sd 0:0:0:0: [sda] Write Protect is off [ 2.312232] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00 [ 2.312269] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [ 2.390450] sda: sda1 sda2 < > [ 2.391245] sd 0:0:0:0: [sda] Attached SCSI disk [ 2.407136] sdb: sdb1 < > sdb2 [ 2.407629] sd 4:0:0:0: [sdb] Attached SCSI disk [ 2.449061] md: bind<sda> [ 2.516626] sr0: scsi3-mmc drive: 24x/24x writer dvd-ram cd/rw xa/form2 cdda tray [ 2.516736] cdrom: Uniform CD-ROM driver Revision: 3.20 [ 2.517189] sr 1:0:0:0: Attached scsi CD-ROM sr0 [ 2.655174] md: bind<sdb> [ 2.662552] md: bind<sdb> [ 2.662919] md: bind<sda> [ 2.664551] md: raid0 personality registered for level 0 [ 2.664915] bio: create slab <bio-1> at 1 [ 2.665005] md/raid0:md126: md_size is 1250275328 sectors. [ 2.665086] md: RAID0 configuration for md126 - 1 zone [ 2.665165] md: zone0=[sda/sdb] [ 2.665419] zone-offset= 0KB, device-offset= 0KB, size= 625137920KB [ 2.665515] [ 2.665632] md126: detected capacity change from 0 to 640140967936 [ 2.800386] md126: p1 p2 < p5 p6 > Bad dmesg: [ 0.000000] Linux version 3.4.0-rc5-ARCH-00007-gc6563a8 (bdowning@saphira) (gcc version 4.7.1 (GCC) ) #15 SMP PREEMPT Tue Jul 17 03:12:25 CDT 2012 [ 0.000000] Command line: root=UUID=89ccd806-db3e-49d2-a338-5efb0c5829dc ro initrd=../initramfs-linux-git.img BOOT_IMAGE=../vmlinuz-linux-git ... [ 2.307932] sd 0:0:0:0: [sda] 625142448 512-byte logical blocks: (320 GB/298 GiB) [ 2.308116] sd 0:0:0:0: [sda] Write Protect is off [ 2.308197] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00 [ 2.308234] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, does n't support DPO or FUA [ 2.308869] sd 4:0:0:0: [sdb] 625142448 512-byte logical blocks: (320 GB/298 GiB) [ 2.309063] sd 4:0:0:0: [sdb] Write Protect is off [ 2.309144] sd 4:0:0:0: [sdb] Mode Sense: 00 3a 00 00 [ 2.309182] sd 4:0:0:0: [sdb] Write cache: enabled, read cache: enabled, does n't support DPO or FUA [ 2.390455] sda: sda1 sda2 < > [ 2.391122] sd 0:0:0:0: [sda] Attached SCSI disk [ 2.400433] sdb: sdb1 < > sdb2 [ 2.400913] sd 4:0:0:0: [sdb] Attached SCSI disk [ 2.465423] md: bind<sdb> [ 2.465723] md: md127 stopped. [ 2.465810] md: unbind<sdb> [ 2.466955] md: export_rdev(sdb) [ 2.472482] md: bind<sda> [ 2.472678] md: md127 stopped. [ 2.472759] md: unbind<sda> [ 2.474539] mdadm: sending ioctl 800c0910 to a partition! [ 2.474620] mdadm: sending ioctl 800c0910 to a partition! [ 2.474796] mdadm: sending ioctl 1261 to a partition! [ 2.474875] mdadm: sending ioctl 1261 to a partition! [ 2.502748] md: export_rdev(sda) [ 2.513095] sr0: scsi3-mmc drive: 24x/24x writer dvd-ram cd/rw xa/form2 cdda tray [ 2.513193] cdrom: Uniform CD-ROM driver Revision: 3.20 [ 2.513664] sr 1:0:0:0: Attached scsi CD-ROM sr0 [ 2.536404] mdadm: sending ioctl 800c0910 to a partition! [ 2.536503] mdadm: sending ioctl 800c0910 to a partition! [ 2.536696] mdadm: sending ioctl 1261 to a partition! [ 2.536794] mdadm: sending ioctl 1261 to a partition! [ 2.537177] mdadm: sending ioctl 1261 to a partition! [ 2.537257] mdadm: sending ioctl 1261 to a partition! (I type in 'mdadm --assemble --scan' here) [ 18.807584] scsi_verify_blk_ioctl: 16 callbacks suppressed [ 18.807666] mdadm: sending ioctl 800c0910 to a partition! [ 18.807746] mdadm: sending ioctl 800c0910 to a partition! [ 18.807836] mdadm: sending ioctl 1261 to a partition! [ 18.807916] mdadm: sending ioctl 1261 to a partition! [ 18.808241] mdadm: sending ioctl 1261 to a partition! [ 18.808322] mdadm: sending ioctl 1261 to a partition! [ 18.808632] mdadm: sending ioctl 1261 to a partition! [ 18.808712] mdadm: sending ioctl 1261 to a partition! [ 18.808973] mdadm: sending ioctl 1261 to a partition! [ 18.809053] mdadm: sending ioctl 1261 to a partition! [ 18.820428] md: md127 stopped. [ 18.826492] md: bind<sda> [ 18.827345] md: bind<sdb> [ 19.058251] md: md126 stopped. [ 19.059035] md: bind<sdb> [ 19.059421] md: bind<sda> [ 19.060988] md: raid0 personality registered for level 0 [ 19.061282] bio: create slab <bio-1> at 1 [ 19.061371] md/raid0:md126: md_size is 1250275328 sectors. [ 19.061452] md: RAID0 configuration for md126 - 1 zone [ 19.061531] md: zone0=[sda/sdb] [ 19.061785] zone-offset= 0KB, device-offset= 0KB, size= 625137920KB [ 19.061881] [ 19.061995] md126: detected capacity change from 0 to 640140967936 [ 19.553668] md126: p1 p2 < p5 p6 > Thanks, -bcd -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html