Dynamics CRM Server-Side Sync allows you to capture logs which could help in troubleshooting any issues with users mailboxes in regards to the Server-Side Sync. The alerts are shown on the Alerts wall or the Alerts section in the mailbox or email server profile records.
This is very interesting for Dynamics Online deployments, without having access to the database. You can cleanup some data from database with a bulk deletion job. It can improve the performance of the organization!
Read more in MSDN blog from Ryan A. Anderson at: https://blogs.msdn.microsoft.com/crminthefield/2017/11/06/is-dynamics-365-server-side-sync-filling-up-your-database/