How to Design the Database for Mailbox Databases

          In process of design Mailbox services, you must identify the information required for both mailboxes and public folders. Typically, the information you gather helps you to determine the size of databases that need to be stored, and the processing load that those databases will
place on the mailbox servers.
          To design mailbox databases, you must think about the following factors related to mailboxes:
• Number of users. A larger number of users typically increases disk utilization.
• Frequency of usage. Higher frequency usage  ypically increases disk utilization.
• Size of mailboxes. Larger mailboxes combined with a higher number of users increases overall
database size.
• Service level agreements (SLAs). To meet the recovery requirements, you may need to keep databases small so that restore times are reduced.