Managing enviroment capacity - database usage

[Termigez1]

I have two different tenants. Each one have many different environments. Recently I have realized that on one tenant (lets say Tenant A) my environment use nearly 3 GB just as database usage, despite the fact, that there are no apps there and noone works there or create new things there. 

On my Tenant B I have 'living' environment, people create Apps, add new tables and data and the Database usage is 1 GB. 

This made me wonder what influence how much Database usage each environment needs? I look at details of environment on Tenant A and see that nearly 0.5 GB is used on something called MailboxBase and I have no idea what it is. Can you provide me with any explanation how Database usage works and how can I reduce it? 

[jukka-niiranen · Accepted solution]

There's a wealth of tables included in every Dataverse environment to facilitate the built-in features of the platform. Especially if you choose to enabled Dynamics 365 features upon environment provisioning (without even installing any Dynamics 365 apps) this will significantly increase the number of system tables. All of these will consume the storage capacity, just like a Windows OS installation on your hard drive consumes space.

MailboxBase is the mailbox table included to allow synchronizing emails, appointments and tasks. Commonly used in CRM scenarios but also in custom apps with activity tracking requirements. Here are the Docs for the feature. You might want to open the list of mailboxes for tenant A and check whether there's a high number of user accounts synchronized into the environment, each with a mailbox and possibly some email synchronization setting causing error logs or other status info to be repeatedly written there to consume space.

As for general guidance on how to reduce Dataverse database storage consumption, here's what Microsoft instructs as steps to free up storage.