I'm pretty new to RAID, so please forgive my silly question.
I have an
Ubuntu Server 12.04 x64 installed on a pc having 4 hdds.
During RAID setup I selected RAID10 and (my ignorance) choose 2 active hdds and 2 spare hdds. I'm pretty sure it's not the optimal configuration and probably I should have selected 4 active hdds.
cat /proc/mdstat I get
md1 : active raid10 sdb2 sdd2(S) sdc2(S) sda2 948736 blocks super 1.2 2 near-copies [2/2] [UU] md0 : active raid10 sdb1 sdd1(S) sdc1(S) sda1 311619072 blocks super 1.2 2 near-copies [2/2] [UU] unused devices: <none>
Is there a way I can convert spare disks to active disks?
I tried using
mdadm --grow /dev/md1 --raid-devices=4, but got this answer
mdadm: RAID10 can only be changed to RAID0