problem with mdstat

[Arnar Gestsson]

Hi,

I have on one of my servers problems with the mirror, cat /proc/mdstat 
shows the following

md4 : active raid1 sdb3[1](F) sda5[0]
      4196224 blocks [2/1] [U_]

I would, due to the lower line, think that the sda5 is out, but the "F" 
bothers me. Do any you know how to handle the situation?

BR. Arnar