On Thu, Nov 29, 2018 at 3:09 AM NeilBrown <neilb@xxxxxxxx> wrote: > > On Wed, Nov 28 2018, Ed Spiridonov wrote: > > I uploaded mdadm --examine output to > > https://bugzilla.kernel.org/show_bug.cgi?id=201331 > > This only shows > Raid Level : raid10 > and > Chunk Size : 512K > > I thought the problem was with RAID6 and a chunk size of 16M ?? Oops, my wrong, I uploaded data of another array. Right 'mdadm --examine' output just uploaded > In any case, an import detail from this is : > > Unused Space : before=98216 sectors, after=32768 sectors > > To perform a reshape-without-a-backup there needs to be at least one > chunk (the larger chunk size) either before or after. So it is Unused Space : before=262056 sectors, after=28639 sectors Anyway it is big enough. > >> >> 2. Is it possible to reshape existing RAID with smaller chunk size? > >> >> (without data loss) > >> > >> Yes. > > > > I have not managed yet. > > Please try without --backup-file. I tried it before, it does nothing too. Here is tail of the strace output,could it help? open("/sys/block/md3/md/metadata_version", O_RDONLY) = 4 read(4, "1.2\n", 1024) = 4 close(4) = 0 open("/sys/block/md3/md//array_state", O_RDWR) = 4 lseek(4, 0, SEEK_SET) = 0 read(4, "clean\n", 20) = 6 close(4) = 0 stat("/sys/block/md3/md//sync_action", {st_mode=S_IFREG|0644, st_size=4096, ...}) = 0 open("/sys/block/md3/md//sync_action", O_RDWR) = 4 lseek(4, 0, SEEK_SET) = 0 read(4, "idle\n", 20) = 5 close(4) = 0 open("/sys/block/md3/md//sync_action", O_WRONLY) = 4 write(4, "frozen", 6) = 6 close(4) = 0 fstat(3, {st_mode=S_IFBLK|0660, st_rdev=makedev(9, 3), ...}) = 0 open("/proc/devices", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0 read(4, "Character devices:\n 1 mem\n 4 /"..., 1024) = 426 read(4, "", 1024) = 0 close(4) = 0 open("/sys/block/md3/md/component_size", O_RDONLY) = 4 read(4, "9694461952\n", 50) = 11 close(4) = 0 ioctl(3, RAID_VERSION, 0x7ffef28ae7f0) = 0 fstat(3, {st_mode=S_IFBLK|0660, st_rdev=makedev(9, 3), ...}) = 0 readlink("/sys/dev/block/9:3", "../../devices/virtual/block/md3", 199) = 31 ioctl(3, GET_ARRAY_INFO, 0x7ffef28ae170) = 0 uname({sysname="Linux", nodename="storage10x10n1", ...}) = 0 stat("/sys/block/md3/md//sync_action", {st_mode=S_IFREG|0644, st_size=4096, ...}) = 0 open("/sys/block/md3/md//sync_action", O_RDWR) = 4 lseek(4, 0, SEEK_SET) = 0 read(4, "frozen\n", 20) = 7 close(4) = 0 ioctl(3, GET_ARRAY_INFO, 0x7ffef28ae170) = 0 open("/sys/block/md3/md//chunk_size", O_WRONLY) = 4 write(4, "4194304", 7) = 7 close(4) = 0 fstat(1, {st_mode=S_IFCHR|0600, st_rdev=makedev(136, 1), ...}) = 0 write(1, "chunk size for /dev/md3 set to 1"..., 40) = 40 open("/sys/block/md3/md/metadata_version", O_RDONLY) = 4 read(4, "1.2\n", 1024) = 4 close(4) = 0 open("/sys/block/md3/md//sync_action", O_RDWR) = 4 lseek(4, 0, SEEK_SET) = 0 read(4, "frozen\n", 20) = 7 close(4) = 0 open("/sys/block/md3/md//sync_action", O_WRONLY) = 4 write(4, "idle", 4) = 4 close(4) = 0 exit_group(0) = ? +++ exited with 0 +++
