Powershell to customize online maintenance schedule. During this interval, tasks like dumpster cleanup (the deletion of messages that have passed their deleted item retention date), deleted mailbox cleanup, and online defragmentation (database objects that are no longer being used are detected and removed, thereby making additional database space available) are performed. These processes keep the Exchange Server computer healthy and the performance stable. Online maintenance should be set to run at least four hours a day; failing to do so will cause performance degradation over time.

Get-MailboxDatabase | Set-MailboxDatabase -MaintenanceSchedule “Sun.1:00 PM-Sun.5:00 PM”,”Mon.1:00 PM-Mon.5:00 PM”, “Tue.1:00 PM-Tue.5:00 PM”, “Wed.1:00 PM-Wed.5:00 PM”,”Thu.1:00 PM-Thu.5:00 PM”, “Fri.1:00 PM-Fri.5:00 PM”,”Sat.1:00 PM-Sat.5:00 PM”