Zimbra - HowTo calculate sizing of storage

STORAGE CALCULATION EXAMPLE
(Based on ‘Mailbox Usage of 200 MB’ and 500 users)

+ User Data: 500 users with 200 MB = 100 GB user data
+ MySQL data: 5% of 100 GB (User Data): 5 GB
+ Zimbra binaries: 10 GB
+ Zimbra logs: 20 GB
+ Zimbra indexes: 25% of 100GB (User Data) = 25 GB

SUBTOTAL: 100 + 5 + 10 + 20 + 25 = 160 GB
Backups: 160 % of Subtotal: 160 * 160% = 256 GB for backups

TOTAL: 160 + 256 = 416 GB

Ref. Zimbra Blog