In this blog post, I’ll show you how to view how much available disk space also known as whitespace is available on Exchange Server 2016 database.
This article will also work on Exchange Server 2010 and 2013.
In Exchange Server, you have the actual mailbox database space that grows when new mailboxes are created or mailboxes increasing in size.
When a mailbox is deleted or moved from the database the actual database files stays the same, however, the available disk space on the database grows.
In practice, when the mailbox database size will grow only when there is no whitespace available.
Below, there is a cmdlet that gets all the Databases on Exchange Server Environment and shows actual DB size and available size.
CMdlet
get-MailboxDatabase -Status | sort name | select name,@{Name='DB Size (Gb)';Expression={$_.DatabaseSize.ToGb()}},@{Name='Available New Mbx Space Gb)';Expression={$_.AvailableNewMailboxSpace.ToGb()}}
It is recommended to use databases with a lot of whitespaces first before using other and once every week or month rebalance mailboxes depending on available disk space.