I have recently tried to add 4 additional devices to a RAID 6 array, with this command: mdadm -G /dev/md1 -n 8 -a /dev/sdb2 /dev/sdf2 /dev/sdg2 /dev/sdh2 Output from the command, I do not have, but it is what I would take as normal - it confirmed what I had asked with no error. dmesg | grep -w md shows this: [ 2.339195] md: bind<sde2> [ 2.339957] md: bind<sdc1> [ 2.341128] md: bind<sdd2> [ 2.342079] md: bind<sdc3> [ 2.342735] md: bind<sdd3> [ 2.343667] md: bind<sdc2> [ 2.344923] md: bind<sdd1> [ 2.345939] md: bind<sde1> [ 2.347212] md: bind<sde3> [ 3.413622] md: bind<sda2> [ 3.660395] md: raid6 personality registered for level 6 [ 3.660396] md: raid5 personality registered for level 5 [ 3.660397] md: raid4 personality registered for level 4 [ 3.660548] md/raid:md1: device sda2 operational as raid disk 0 [ 3.660550] md/raid:md1: device sdc2 operational as raid disk 1 [ 3.660551] md/raid:md1: device sdd2 operational as raid disk 2 [ 3.660552] md/raid:md1: device sde2 operational as raid disk 3 [ 3.660844] md/raid:md1: allocated 0kB [ 3.660862] md/raid:md1: raid level 6 active with 4 out of 4 devices, algorithm 2 [ 3.731726] md: bind<sda3> [ 3.733039] md: raid0 personality registered for level 0 [ 3.733168] md/raid0:md2: md_size is 234129408 sectors. [ 3.733170] md: RAID0 configuration for md2 - 1 zone [ 3.733171] md: zone0=[sda3/sdd3/sde3] [ 3.739588] md: bind<sda1> [ 3.759253] md: raid1 personality registered for level 1 [ 3.759429] md/raid1:md0: active with 4 out of 4 mirrors [ 3.918565] md: array md3 already has disks! [ 3.918697] md: bind<md2> [ 3.919332] md: linear personality registered for level -1 [ 2733.499792] md: bind<sdb1> [ 2735.135587] md: bind<sdf1> [ 2735.256588] md: bind<sdg1> [ 2735.402403] md: could not open unknown-block(8,81). [ 2735.402412] md: md_import_device returned -16 [ 2735.402428] md: could not open unknown-block(8,81). [ 2735.402432] md: md_import_device returned -16 [ 2735.447468] md: bind<sdh1> [ 2735.741173] md: recovery of RAID array md0 [ 2735.741174] md: minimum _guaranteed_ speed: 1000 KB/sec/disk. [ 2735.741175] md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for recovery. [ 2735.741183] md: using 128k window, over a total of 96256k. [ 2745.098791] md: md0: recovery done. [ 2779.774452] md: bind<sdb2> [ 2779.887067] md: bind<sdf2> [ 2780.051949] md: bind<sdg2> [ 2780.162323] md: bind<sdh2> [ 2780.559396] md: reshape of RAID array md1 [ 2780.559399] md: minimum _guaranteed_ speed: 1000 KB/sec/disk. [ 2780.559400] md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for reshape. [ 2780.559408] md: using 128k window, over a total of 205077632k. (note: I have already tried adjusting the minimum speed) /proc/mdstat is looking like this: Personalities : [raid6] [raid5] [raid4] [raid0] [raid1] [linear] md2 : active raid0 sda3[0] sde3[2] sdd3[1] 117064704 blocks super 1.2 512k chunks md3 : active linear md2[0] sdc3[1] 400277156 blocks super 1.2 0k rounding md0 : active raid1 sdh1[4] sdg1[5] sdf1[6] sdb1[7] sda1[0] sde1[3] sdd1[1] sdc1[ 2] 96256 blocks [8/8] [UUUUUUUU] bitmap: 0/12 pages [0KB], 4KB chunk md1 : active raid6 sdh2[4] sdg2[5] sdf2[6] sdb2[7] sda2[0] sdc2[1] sdd2[2] sde2[ 3] 410155264 blocks super 0.91 level 6, 64k chunk, algorithm 2 [8/8] [UUUUUUU U] [>....................] reshape = 0.0% (0/205077632) finish=39282834032. 1min speed=0K/sec bitmap: 10/196 pages [40KB], 512KB chunk unused devices: <none> mdadm --detail /dev/md1 gives: /dev/md1: Version : 0.91 Creation Time : Sat Oct 4 15:01:57 2008 Raid Level : raid6 Array Size : 410155264 (391.15 GiB 420.00 GB) Used Dev Size : 205077632 (195.58 GiB 210.00 GB) Raid Devices : 8 Total Devices : 8 Preferred Minor : 1 Persistence : Superblock is persistent Intent Bitmap : Internal Update Time : Wed Oct 14 18:09:32 2015 State : clean, reshaping Active Devices : 8 Working Devices : 8 Failed Devices : 0 Spare Devices : 0 Layout : left-symmetric Chunk Size : 64K Reshape Status : 0% complete Delta Devices : 4, (4->8) UUID : 7b4ddd0f:d04e8dbf:93c13954:ca72c56a Events : 0.5558446 Number Major Minor RaidDevice State 0 8 2 0 active sync /dev/sda2 1 8 34 1 active sync /dev/sdc2 2 8 50 2 active sync /dev/sdd2 3 8 66 3 active sync /dev/sde2 4 8 114 4 active sync /dev/sdh2 5 8 98 5 active sync /dev/sdg2 6 8 82 6 active sync /dev/sdf2 7 8 18 7 active sync /dev/sdb2 What can I safely do to move this along? -- Phil Reynolds mail: phil@xxxxxxxxxxxxxxxxxx Web: http://phil.tinsleyviaduct.com/ -- 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