December 28, 2015

Lab 17.1 Creating Software Raid - mdadm: RUN_ARRAY failed: Invalid argument

I'm using the LFS Ubuntu 14.1 lab VM.

Basically, I added an additional 1GB virtual drive to the VM in Virtualbox. Partitioned it with fdisk.
pvcreate /dev/sdb1
vgcreate VG /dev/sdb1
lvcreate -L 200M -n MD1 VG
lvcreate -L 200M -n MD2 VG

root@ubuntu:/home/student# lvdisplay
--- Logical volume ---
LV Path /dev/VG/MD1
LV Name MD1
VG Name VG
LV UUID BVR2X8-jltC-MCSd-WulR-2IXQ-uc7c-6SEjvr
LV Write Access read/write
LV Creation host, time ubuntu, 2015-12-28 15:16:00 -0600
LV Status available
# open 0
LV Size 200.00 MiB
Current LE 50
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 252:0

--- Logical volume ---
LV Path /dev/VG/MD2
LV Name MD2
VG Name VG
LV UUID A8P9JO-RKwK-XlUB-Ifw7-mrtI-yfFO-zV3lQY
LV Write Access read/write
LV Creation host, time ubuntu, 2015-12-28 15:16:03 -0600
LV Status available
# open 0
LV Size 200.00 MiB
Current LE 50
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 252:1

root@ubuntu:/home/student# mdadm --create --verbose /dev/md0 --level=mirror --raid-devices=2 /dev/VG/MD1 /dev/VG/MD2
mdadm: Note: this array has metadata at the start and
may not be suitable as a boot device. If you plan to
store '/boot' on this device please ensure that
your boot-loader understands md/v1.x metadata, or use
--metadata=0.90
mdadm: size set to 204608K
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: RUN_ARRAY failed: Invalid argument

root@ubuntu:/home/student# cat /proc/mdstat
Personalities :
unused devices: <none>

I've also tried adding 2x 1GB virtual disks in Virtualbox, then trying to create a raid array with those 2 disks. Same error "mdadm: RUN_ARRAY failed: Invalid argument"

After battling with this for a few hours, reading man pages, and googling, I'm still getting the error.

Click Here!