I was working on a CRM 2011 system that had several million system job records in it, and the number of records was growing very rapidly. The database had reached a size of over 120 gigabytes, and the number of continually growing system jobs was becoming an administrative and performance issue. I explain in this blog post how I analyzed and prevented the accumulation of new system jobs and deleted the existing ones. All of this information is still relevant to newer versions of CRM.
I recently updated a CRM server to the newest update rollup version, and found afterwards the CRM server was configured to not automatically update all the organizations when update rollups are installed. To handle this post-upgrade situation, I wrote a PowerShell script to automate the update of the organizations rather than manually updating each organization one at a time through the deployment manager user interface.