Drives are running out of free space (SharePoint Server)
APPLIES TO: 
2013 2016 2019 Subscription Edition 
SharePoint in Microsoft 365
Rule Name: Drives are running out of free space.
Summary: Disk drives on one or more of the servers in the SharePoint Server farm are running out of disk space.
Note
This rule checks disk space as a proportion of the RAM that is installed on the computer. When disk space is less than twice the RAM on the computer, the health rule triggers an error. When disk space is less than five times the RAM on the server, the health rule triggers a warning. Servers with large amounts of RAM are more likely to experience a failure of this rule.
Resolution: Free disk space on the server
Verify that the user account that is performing this procedure is a member of the Farm Administrators group.
In Server Manager, click Tools, and then click Disk Cleanup.
Resolution: Decrease the number of days to store log files
Verify that the user account that is performing this procedure is a member of the Farm Administrators group.
On the SharePoint Central Administration website, click Monitoring, in the Reporting section, click Configure diagnostic logging.
On the Diagnostic Logging page, in the Trace Log section, in the Number of days to store log files box, type a smaller number.
Click OK.