Use the menu in the top right of the screen to select settings; Set how miniDBA operates and samples new server instances under the General tab.
The "Maximum Log Storage Mb" field controls how much historical performance data is kept. Once the storage exceeds the setting, the oldest day(s) are deleted.
Set how miniDBA sends emails under the Email tab.
Enter the details of your SMTP server if you want miniDBA Server to send emails when alerts occur.
After entering smtp server details use the "Test" button to send a test email to verify your server details.