Doesn't work since sdb has been ejected. Strace below. package manager: mdadm 3.3-r2 #mdadm -V: mdadm - v3.3 - 3rd September 2013 Just tried 3.3-r3 and 3.2.6-r1 same issue. (There are no older in the package manager to try fast.) #strace mdadm /dev/md126 -r /dev/sdb2 execve("/sbin/mdadm", ["mdadm", "/dev/md126", "-r", "/dev/sdb2"], [/* 99 vars */]) = 0 uname({sys="Linux", node="********", ...}) = 0 brk(0) = 0x212d000 brk(0x212e1c0) = 0x212e1c0 arch_prctl(ARCH_SET_FS, 0x212d880) = 0 brk(0x214f1c0) = 0x214f1c0 brk(0x2150000) = 0x2150000 time(NULL) = 1407569631 getpid() = 6499 open("/dev/md126", O_RDWR) = 3 fstat(3, {st_mode=S_IFBLK|0660, st_rdev=makedev(9, 126), ...}) = 0 ioctl(3, RAID_VERSION, 0x7ffffed2ffa0) = 0 open("/etc/mdadm.conf", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=286, ...}) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=286, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f804b529000 read(4, "ARRAY /dev/md/main metadata=1.2 "..., 4096) = 286 read(4, "", 4096) = 0 read(4, "", 4096) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=286, ...}) = 0 close(4) = 0 munmap(0x7f804b529000, 4096) = 0 open("/etc/mdadm.conf.d", O_RDONLY) = -1 ENOENT (No such file or directory) uname({sys="Linux", node="*********", ...}) = 0 geteuid() = 0 ioctl(3, GET_ARRAY_INFO, 0x7ffffed2fd70) = ioctl(3, RAID_VERSION, 0x7ffffed2fc50) = 0 fstat(3, {st_mode=S_IFBLK|0660, st_rdev=makedev(9, 126), ...}) = 0 readlink("/sys/dev/block/9:126", "../../devices/virtual/block/md12"..., 199) = 33 fstat(3, {st_mode=S_IFBLK|0660, st_rdev=makedev(9, 126), ...}) = 0 open("/proc/devices", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f804b529000 read(4, "Character devices:\n 1 mem\n 2 p"..., 1024) = 734 read(4, "", 1024) = 0 close(4) = 0 munmap(0x7f804b529000, 4096) = 0 open("/sys/block/md126/md/component_size", O_RDONLY) = 4 read(4, "102272\n", 50) = 7 close(4) = 0 ioctl(3, RAID_VERSION, 0x7ffffed2daf0) = 0 fstat(3, {st_mode=S_IFBLK|0660, st_rdev=makedev(9, 126), ...}) = 0 readlink("/sys/dev/block/9:126", "../../devices/virtual/block/md12"..., 199) = 33 open("/sys/block/md126/md/metadata_version", O_RDONLY) = 4 read(4, "1.2\n", 1024) = 4 close(4) = 0 fstat(3, {st_mode=S_IFBLK|0660, st_rdev=makedev(9, 126), ...}) = 0 readlink("/sys/dev/block/9:126", "../../devices/virtual/block/md12"..., 199) = 33 open("/dev/sdb2", O_RDONLY|O_DIRECT) = -1 ENOENT (No such file or directory) stat("/dev/sdb2", 0x7ffffed2fe10) = -1 ENOENT (No such file or directory) write(2, "mdadm: Cannot find /dev/sdb2: No"..., 56mdadm: Cannot find /dev/sdb2: No such file or directory ) = 56 exit_group(1) = ? +++ exited with 1 +++ Killian De Volder On 09-08-14 02:49, NeilBrown wrote: > On Sat, 09 Aug 2014 00:10:13 +0200 Killian De Volder > <killian.de.volder@xxxxxxxxxxx> wrote: > >> I'm having some trouble with a disk of unknown cause. >> As a result the disk is now "failed" >> >> #dmesg >> [362288.463008] ata3: exception Emask 0x10 SAct 0x0 SErr 0x90202 action 0xe frozen >> ... >> [377997.666956] md: super_written gets error=-5, uptodate=0 >> [377997.666960] md/raid1:md126: Disk failure on sdb3, disabling device >> >> I replugged the disk, and added it again to the raid (it is now called sdf instead of sdb): >> >> # cat /proc/mdstat: >> md126 : active raid1 sdf2[5] sdd2[0] sde2[3] sdc2[2] sdb2[4](F) >> 102272 blocks super 1.2 [4/4] [UUUU] >> >> So I wanted to remove the failed disk: >> >> # mdadm /dev/md126 -r failed >> mdadm: Cannot find 8:18: No such file or directory > Hmm.. that looks broken. > What version of mdadm is this? > Does > mdadm /dev/md126 -r detached > work? > How about > mdadm /dev/md127 -r sdb2 > > Thanks, > NeilBrown -- 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