MailGate must be configured to use an external storage. What are the guidelines in estimating how much space to dedicate on the external storage for secure packages?

You can estimate the approximate space required on the external storage (forecast) by multiplying the following numbers specific to your environment:

1. Number of Secure Mailbox users
2. Average number of secure messages a user receives per day
3. Number of days the messages will be available for the user (message expiration time)
4. Average secure message size

It is a good practice to dedicate +20% more space to ensure that you do not accidentally run out of space on the external storage.