When I do a cat /proc/mdstat I get the following results.
# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdd1 sdc1 sdb1 sda1
4395407808 blocks level 5, 64k chunk, algorithm 2 [4/3] [UUU_]
[===========>.........] recovery = 59.5% (871892528/1465135936) finish=949.8min speed=10408K/sec
unused devices: <none>
The question is do the [UUU_] flags match the drives in the order displayed sdd1 sdc1 sdb1 sda1?
If so then sda1 is the bad drive in this scenario, or do I look at the number after the drive device in this case the  position would indicate sdd1 as the bad drive.
Thank you in advance.