+ This file responds to select/poll. Any important change in the value
+ triggers a poll event. Sometimes the value will briefly be
+ "recover" if a recovery seems to be needed, but cannot be
+ achieved. In that case, the transition to "recover" isn't
+ notified, but the transition away is.
+
+ degraded
+ This contains a count of the number of devices by which the
+ arrays is degraded. So an optimal array with show '0'. A
+ single failed/missing drive will show '1', etc.
+ This file responds to select/poll, any increase or decrease
+ in the count of missing devices will trigger an event.
+