Setting Service Maintenance Time
Each environment requires up to one hour every day to perform routine maintenance. Service Administrators can select (and change) the most convenient time to start the maintenance window.
In addition to routine maintenance, Oracle applies required patches (for example, monthly updates) to the environment and creates maintenance snapshots and Activity Reports during the maintenance window.
The new maintenance snapshot replaces the previous snapshot. Oracle recommends that you download the snapshot daily to backup the environment. See Backing Up and Restoring an Environment Using the Maintenance Snapshot
Because the environment is not available to users during the maintenance window, the Service Administrator should identify a one-hour period when no one uses the service. Any connected user will be logged off and will lose unsaved data.
Note:
To allow users to save their data, Oracle Enterprise Performance Management Cloud displays a notice of impending maintenance 15 minutes before the maintenance process starts.The default maintenance start time is between 10:00 p.m. and 1:00 a.m. local time of the data center that hosts your environment. If you do not reset the default start time for an environment, Oracle randomizes it to start between 10:00 p.m. and 1:00 a.m. local time of the data center. After you select a maintenance start time, Oracle honors your selection.
Some services may perform additional maintenance operations. For example, Planning Modules, Account Reconciliation, and Financial Consolidation and Close may require additional maintenance time for content upgrade. EPM Cloud environments are available only to Service Administrators during such maintenance periods.
Note:
Additionally, because of planned daily maintenance, the status of the environment in My Services console is always displayed as Planned Maintenance (in yellow) even if your environment has no other planned maintenance. 
To set the maintenance start time: