Oracle database instance recovery is taking too much time after shutdown immediate

1.We were going to open DB after shutdown immediate but it went hang.In alert log , we could only notice following message for 40 minutes.   Completed: ALTER DATABASE MOUNT Tue Oct 31 01:08:39 2017 ALTER DATABASE OPEN Beginning crash recovery of 1 threadsparallel recovery started with 9 processes Started redo scanTue Oct 31 01:08:58Continue reading Oracle database instance recovery is taking too much time after shutdown immediate