This counts complete failures this DS3 IMA group has experienced, during start-up or normal operation, since it was added; a partial degradation like one link out of three going down doesn't count, and a group stuck in a failure loop only increments this by 1 regardless of how many times it retries. An admin treats a rising count as evidence of a group that keeps failing outright rather than just running degraded, which usually warrants deeper investigation than the individual link counters alone.