Sal
NRSM initially saves a snapshot of /proc/mdstat in its database. Mine looks like this:
md3 : active raid5 sdd1[3] sdc1[2] sdb1[1] sda1[0]
2930279424 blocks level 5, 256k chunk, algorithm 2 [4/4] [UUUU]
md2 : active raid1 hda2[0]
244091520 blocks [2/2] [UU]
md1 : active raid1 hda1[0]
104320 blocks [2/2] [UU]
unused devices: <none>
With every refresh it compares the current /proc/mdstat with the saved one. Any change, even the slightest difference will raise a Failure warning. You can test this by opening the servers.mdb with M$ Access and make a small change in the RAID_Status field. NRSM will most definitely raise a Failure. I am confident that you lost your drive before you accepted the initial value of /proc/mdstat. An example of a lost drive would look something like this:
md3 : active raid5 sdd1[3] sdc1[2] sdb1[1] sda1[0]
2930279424 blocks level 5, 256k chunk, algorithm 2 [4/4] [UUUU]
md2 : active raid1 hda2[0]
244091520 blocks [2/1] [U_]
md1 : active raid1 hda1[0]
104320 blocks [2/1] [U_]
unused devices: <none>