This is an Exadata wait event that occurs during the shutdown of a storage cell. This is normal activity associated with shutdown processing.
Solutions
If there are queries waiting on this event, it may indicate that your storage cell is in progress of shutting down and the query is forced to wait.
本文转自maclean_007 51CTO博客，原文链接:http://blog.51cto.com/maclean/1277887
