On 12/05/2015 10:04 PM, David Waite wrote: > I’m having difficulty shrinking down a RAID6 array (md2) on a Sinology NAS. I wish to go from 13 drives to 11, and believe I need to go to 12 first to maintain operation and redundancy through the resizing process. No, you can go straight to 11 if you've set array-size properly. --grow operations maintain redundancy throughout. > The -array-size has already been shrunk to account for the two drives I wish to remove, and one of the devices has been removed and the machine restarted before the command output below was generated. You might need to set array-size again. It is a temporary setting that only becomes permanent when --grow successfully starts. > # cat /proc/mdstat > Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] > md2 : active raid6 sda3[0] sdia3[14] sdib3[9] sdic3[10] sdid3[11] sdie3[12] sdg3[17] sdf3[5] sde3[16] sdd3[3] sdc3[13] sdb3[15] > 26329895935 blocks super 1.2 level 6, 64k chunk, algorithm 2 [13/12] [UUUUUUU_UUUUU] > > md1 : active raid1 sda2[0] sdb2[1] sdc2[2] sdd2[3] sde2[4] sdf2[5] sdg2[6] > 2097088 blocks [8/7] [UUUUUUU_] > > md0 : active raid1 sda1[0] sdb1[1] sdc1[2] sdd1[3] sde1[4] sdf1[5] sdg1[6] > 2490176 blocks [8/7] [UUUUUUU_] > > unused devices: <none> > When running > # mdadm --grow -n 12 /dev/md2 --backup-file=/mnt/backup-file3 > mdadm: max_devs [384] of [/dev/md2] > mdadm: Need to backup 7040K of critical section.. > mdadm: Cannot set device shape for /dev/md2: Invalid argument > > --- > > dmesg just reports: > [87908.606245] md: couldn't update array info. -22 Error code 22 is "Invalid Argument", corresponding to the mdadm output. Try setting array size again, then try again. Feel free to go straight to 11 devices -- it'll save you much time. Also, for completeness, show --detail and --examine for the array and it members. Phil -- 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
