On some systems I see this :
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath] [faulty]
md1 : active raid1 sdb1[1] sda1[0]
10485696 blocks [2/2] [UU]
md2 : active raid1 sdb2[1] sda2[0]
477371328 blocks [2/2] [UU]
And other systems show :
Personalities : [raid1]
md0 : active raid1 sdb2[1] sda2[0]
204788 blocks super 1.0 [2/2] [UU]
md1 : active raid1 sdb1[1] sda1[0]
4193272 blocks super 1.1 [2/2] [UU]
md2 : active raid1 sda3[0] sdb3[1]
483985276 blocks super 1.1 [2/2] [UU]
bitmap: 0/4 pages [0KB], 65536KB chunk
I wonder what is the meaning of Personalities and the impact of having different values.