Package: mdadm Version: 3.2.3-2 Severity: normal I have a system with mdadm components (0.90 superblocks) that are on partitions which end close to the end of the disk.
Running "mdadm --assemble --scan" (as happens in the initramfs) fails to initialize the array, and prints this message: mdadm: WARNING /dev/sdb1 and /dev/sdb appear to have very similar superblocks. If they are really different, please --zero the superblock on one If they are the same or overlap, please remove one from the DEVICE list in mdadm.conf Of course, any normal human sysadmin can look at this and say "sdb1 overlaps with sdb". So it seems that mdadm could use an improved heuristic to judge this not-uncommon situation and deal with it without presenting the user with a failure: If mdadm sees matching 0.90 superblocks on two devices, and both devices can fit the superblock's "Used dev size", then choose the smaller of the two devices. Alternately, the heuristic could just verify the special case of a partition and its parent disk (e.g. via major and minor number comparisons). Either way, mdadm should be friendlier to the user when this situation arises. manually configuring mdadm.conf to only look at partitions (and ignore full disks) is kind of a pain: DEVICE /dev/[hs]d*[123456789]* (and of course this wouldn't be acceptable for people using whole disks as mdadm components). fwiw, another component that has avoidable trouble in this situation is grub. I'm working with grub's upstream to improve their heuristics for handling situations like this, and hope to see this fixed there shortly [0]. It'd be nice to have mdadm be comparably capable. --dkg [0] https://lists.gnu.org/archive/html/grub-devel/2012-02/msg00003.html -- Package-specific info: --- mdadm.conf CREATE owner=root group=disk mode=0660 auto=yes HOMEHOST <system> MAILADDR root ARRAY /dev/md0 UUID=f43d27b8:268cb667:f364ebb9:997ca579 DEVICE /dev/sd*[123456789]* --- /etc/default/mdadm INITRDSTART='all' AUTOSTART=true AUTOCHECK=false START_DAEMON=false DAEMON_OPTIONS="--syslog" VERBOSE=false --- /proc/mdstat: Personalities : [raid1] md0 : active raid1 sdb1[0] sda2[1] 13256064 blocks [2/2] [UU] unused devices: <none> --- /proc/partitions: major minor #blocks name 8 0 19531250 sda 8 1 6266913 sda1 8 2 13256178 sda2 8 16 13260240 sdb 8 17 13258192 sdb1 9 0 13256064 md0 253 0 3145728 dm-0 --- LVM physical volumes: PV VG Fmt Attr PSize PFree /dev/md0 vg_trash0 lvm2 a-- 12.64g 9.64g --- mount output sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime) proc on /proc type proc (rw,nosuid,nodev,noexec,relatime) udev on /dev type devtmpfs (rw,relatime,size=575960k,nr_inodes=143990,mode=755) devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000) tmpfs on /run type tmpfs (rw,nosuid,noexec,relatime,size=116268k,mode=755) /dev/mapper/vg_trash0-root on / type ext3 (rw,relatime,errors=remount-ro,user_xattr,acl,barrier=1,data=ordered) tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k) tmpfs on /tmp type tmpfs (rw,nosuid,nodev,relatime,size=232532k) tmpfs on /run/shm type tmpfs (rw,nosuid,nodev,relatime,size=232532k) --- initrd.img-3.2.0-1-686-pae: 50965 blocks f4fbd9099399ab08ba9b9f6c71d77595 ./scripts/local-top/mdadm f302d7280873929e74ea5437988a6d12 ./etc/mdadm/mdadm.conf f93000eb15384550f1ec601e01162ed2 ./sbin/mdadm 67fe47b4ab8e627ba0e4094250b22253 ./lib/modules/3.2.0-1-686-pae/kernel/drivers/md/dm-mirror.ko 416e902eaf5ce942d352f3c462cc6e79 ./lib/modules/3.2.0-1-686-pae/kernel/drivers/md/dm-log.ko 1ed7d2a172a00705fc8060303ae8948c ./lib/modules/3.2.0-1-686-pae/kernel/drivers/md/dm-snapshot.ko b3e11d99443be45593d01faffbd03bea ./lib/modules/3.2.0-1-686-pae/kernel/drivers/md/linear.ko cc530b4c71ebdddb7f3044520731443e ./lib/modules/3.2.0-1-686-pae/kernel/drivers/md/raid1.ko ec45856a2754214704ad051cfb2758ef ./lib/modules/3.2.0-1-686-pae/kernel/drivers/md/raid0.ko 118a27a5a6cad2998f4fa444a09c5889 ./lib/modules/3.2.0-1-686-pae/kernel/drivers/md/multipath.ko 57040ba2184e1a11ec88647e45361731 ./lib/modules/3.2.0-1-686-pae/kernel/drivers/md/raid456.ko d012a5d397b8ecc431857d14812c6a02 ./lib/modules/3.2.0-1-686-pae/kernel/drivers/md/md-mod.ko ef75cc7354e8e1b079ae53a56b763bfe ./lib/modules/3.2.0-1-686-pae/kernel/drivers/md/dm-mod.ko 5e732d5abcb5898dd8479521975c6ae6 ./lib/modules/3.2.0-1-686-pae/kernel/drivers/md/dm-region-hash.ko c846a6c6c6eb59d88091a654d9f9154c ./lib/modules/3.2.0-1-686-pae/kernel/drivers/md/raid10.ko --- initrd's /conf/conf.d/md: MD_HOMEHOST='trash' MD_DEVPAIRS='/dev/md0:raid1' MD_LEVELS='raid1' MD_DEVS=all MD_MODULES='raid1' --- /proc/modules: dm_mod 57278 3 - Live 0xf82fd000 raid1 26218 1 - Live 0xf82c9000 md_mod 85719 2 raid1, Live 0xf832f000 --- /var/log/syslog: --- volume detail: /dev/sda: Magic : a92b4efc Version : 0.90.00 UUID : f43d27b8:268cb667:f364ebb9:997ca579 Creation Time : Fri Feb 24 02:59:43 2012 Raid Level : raid1 Used Dev Size : 13256064 (12.64 GiB 13.57 GB) Array Size : 13256064 (12.64 GiB 13.57 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 0 Update Time : Sat Feb 25 21:24:26 2012 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Checksum : f0315348 - correct Events : 20 Number Major Minor RaidDevice State this 1 8 2 1 active sync /dev/sda2 0 0 8 17 0 active sync /dev/sdb1 1 1 8 2 1 active sync /dev/sda2 -- /dev/sda1 is not recognised by mdadm. /dev/sda2: Magic : a92b4efc Version : 0.90.00 UUID : f43d27b8:268cb667:f364ebb9:997ca579 Creation Time : Fri Feb 24 02:59:43 2012 Raid Level : raid1 Used Dev Size : 13256064 (12.64 GiB 13.57 GB) Array Size : 13256064 (12.64 GiB 13.57 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 0 Update Time : Sat Feb 25 21:24:26 2012 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Checksum : f0315348 - correct Events : 20 Number Major Minor RaidDevice State this 1 8 2 1 active sync /dev/sda2 0 0 8 17 0 active sync /dev/sdb1 1 1 8 2 1 active sync /dev/sda2 -- /dev/sdb: Magic : a92b4efc Version : 0.90.00 UUID : f43d27b8:268cb667:f364ebb9:997ca579 Creation Time : Fri Feb 24 02:59:43 2012 Raid Level : raid1 Used Dev Size : 13256064 (12.64 GiB 13.57 GB) Array Size : 13256064 (12.64 GiB 13.57 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 0 Update Time : Sat Feb 25 21:24:26 2012 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Checksum : f0315355 - correct Events : 20 Number Major Minor RaidDevice State this 0 8 17 0 active sync /dev/sdb1 0 0 8 17 0 active sync /dev/sdb1 1 1 8 2 1 active sync /dev/sda2 -- /dev/sdb1: Magic : a92b4efc Version : 0.90.00 UUID : f43d27b8:268cb667:f364ebb9:997ca579 Creation Time : Fri Feb 24 02:59:43 2012 Raid Level : raid1 Used Dev Size : 13256064 (12.64 GiB 13.57 GB) Array Size : 13256064 (12.64 GiB 13.57 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 0 Update Time : Sat Feb 25 21:24:26 2012 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Checksum : f0315355 - correct Events : 20 Number Major Minor RaidDevice State this 0 8 17 0 active sync /dev/sdb1 0 0 8 17 0 active sync /dev/sdb1 1 1 8 2 1 active sync /dev/sda2 -- --- /proc/cmdline BOOT_IMAGE=/boot/vmlinuz-3.2.0-1-686-pae root=/dev/mapper/vg_trash0-root ro quiet --- grub2: insmod raid set root='(vg_trash0-root)' insmod raid set root='(vg_trash0-root)' insmod raid set root='(vg_trash0-root)' linux /boot/vmlinuz-3.2.0-1-686-pae root=/dev/mapper/vg_trash0-root ro quiet insmod raid set root='(vg_trash0-root)' linux /boot/vmlinuz-3.2.0-1-686-pae root=/dev/mapper/vg_trash0-root ro single --- udev: ii udev 175-3.1 /dev/ and hotplug management daemon 6df86db16655769fa94086d3ee13453a /lib/udev/rules.d/64-md-raid.rules --- /dev: brw-rw---T 1 root disk 9, 0 Feb 25 21:09 /dev/md0 /dev/disk/by-id: total 0 lrwxrwxrwx 1 root root 9 Feb 25 21:09 ata-QUANTUM_FIREBALLP_LM13_883011560304 -> ../../sdb lrwxrwxrwx 1 root root 10 Feb 25 21:09 ata-QUANTUM_FIREBALLP_LM13_883011560304-part1 -> ../../sdb1 lrwxrwxrwx 1 root root 9 Feb 25 21:09 ata-WDC_WD200BB-75DEA0_WD-WMAD21424320 -> ../../sda lrwxrwxrwx 1 root root 10 Feb 25 21:09 ata-WDC_WD200BB-75DEA0_WD-WMAD21424320-part1 -> ../../sda1 lrwxrwxrwx 1 root root 10 Feb 25 21:09 ata-WDC_WD200BB-75DEA0_WD-WMAD21424320-part2 -> ../../sda2 lrwxrwxrwx 1 root root 10 Feb 25 21:09 dm-name-vg_trash0-root -> ../../dm-0 lrwxrwxrwx 1 root root 10 Feb 25 21:09 dm-uuid-LVM-wLdusu0VcjglKWQSWTmYM2kjGf4SvsUT3RtopkVowsNy7R4Kfwag8WxsYpWHdMSv -> ../../dm-0 lrwxrwxrwx 1 root root 9 Feb 25 21:09 md-uuid-f43d27b8:268cb667:f364ebb9:997ca579 -> ../../md0 lrwxrwxrwx 1 root root 9 Feb 25 21:09 scsi-SATA_QUANTUM_FIREBAL883011560304 -> ../../sdb lrwxrwxrwx 1 root root 10 Feb 25 21:09 scsi-SATA_QUANTUM_FIREBAL883011560304-part1 -> ../../sdb1 lrwxrwxrwx 1 root root 9 Feb 25 21:09 scsi-SATA_WDC_WD200BB-75DWD-WMAD21424320 -> ../../sda lrwxrwxrwx 1 root root 10 Feb 25 21:09 scsi-SATA_WDC_WD200BB-75DWD-WMAD21424320-part1 -> ../../sda1 lrwxrwxrwx 1 root root 10 Feb 25 21:09 scsi-SATA_WDC_WD200BB-75DWD-WMAD21424320-part2 -> ../../sda2 /dev/disk/by-path: total 0 lrwxrwxrwx 1 root root 9 Feb 25 21:09 pci-0000:00:1f.1-scsi-0:0:0:0 -> ../../sda lrwxrwxrwx 1 root root 10 Feb 25 21:09 pci-0000:00:1f.1-scsi-0:0:0:0-part1 -> ../../sda1 lrwxrwxrwx 1 root root 10 Feb 25 21:09 pci-0000:00:1f.1-scsi-0:0:0:0-part2 -> ../../sda2 lrwxrwxrwx 1 root root 9 Feb 25 21:09 pci-0000:00:1f.1-scsi-1:0:0:0 -> ../../sdb lrwxrwxrwx 1 root root 10 Feb 25 21:09 pci-0000:00:1f.1-scsi-1:0:0:0-part1 -> ../../sdb1 /dev/disk/by-uuid: total 0 lrwxrwxrwx 1 root root 10 Feb 25 21:09 f7631934-2b10-47c3-b06f-f9da71e0fd30 -> ../../dm-0 /dev/md: total 0 Auto-generated on Sat, 25 Feb 2012 21:25:16 +0000 by mdadm bugscript 3.2.3-2 -- System Information: Debian Release: wheezy/sid APT prefers unstable APT policy: (500, 'unstable') Architecture: i386 (i686) Kernel: Linux 3.2.0-1-686-pae (SMP w/1 CPU core) Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Versions of packages mdadm depends on: ii debconf 1.5.41 ii initscripts 2.88dsf-22 ii libc6 2.13-26 ii lsb-base 3.2-28.1 ii udev 175-3.1 Versions of packages mdadm recommends: ii default-mta | mail-transport-agent <none> ii module-init-tools 3.16-1 mdadm suggests no packages. -- debconf information: mdadm/initrdstart_msg_errexist: mdadm/mail_to: root mdadm/initrdstart_msg_errmd: * mdadm/initrdstart: all mdadm/initrdstart_msg_intro: mdadm/autostart: true mdadm/initrdstart_msg_errconf: * mdadm/autocheck: false mdadm/initrdstart_notinconf: false mdadm/initrdstart_msg_errblock: * mdadm/start_daemon: false -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". 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