Exchange Server DB capacity planning formula

Database size = Number of mailboxes Mailbox size on disk Database overhead growth factor

Mailbox size on disk = Mailbox quota + White space + Garbage station size

Mailbox quota: mailbox size per user

White space: The size of mail sent and received daily by mailboxes in the database

Garbage Bin Size: (Average Daily Incoming and Outgoing Message Size Deleted Item Retention Period)+(Mailbox Quota Size 0.012)+(Mailbox Quota Size 0.058)

Deleted items retention period defaults to 14 days

Database overhead growth factor is typically 20%

Examples:

·2117 users, 13 databases, 100 emails per day, 500MB per mailbox quota, average mail size 150K

Calculated as follows:

·Number of users per database: 2117/13=200 mailboxes

White space: 100150K/1024=15M

Size of garbage station: (100150K14)/1024 +(1024M0.012)+(1024M0.058)= 277M

Then mailbox size per user =500M+15M+277M=800M

Database Size =200800M1.2=192G

13 libraries total disk space 192G13=2.5TB