Maintenance window
In information technology and systems management, a maintenance window is a period of time designated in advance by the technical staff, during which preventive maintenance that could cause disruption of service may be performed. == High availability services == For a high-availability service, such as an Internet hosting service or Internet service provider, the purpose of stating a time period in advance is to allow clients of the service to prepare for possible disruption or prepare for any major changes to the functioning of the service.