title: ORA-02065: illegal option for ALTER SYSTEM
body: <p>I'm new to Oracle. I was learning Backup and Recovery. For that, I did</p>
  <blockquote>
  <p>$ sqlplus system/password</p>
  <p>SQL&gt; alter system set db_recovery_file_dest_size=8gb scope=both;</p>
  </blockquote>
  <p>But I got error this error:-<a href="https://i.stack.imgur.com/TQ3qD.png" rel="nofollow noreferrer">enter image description here</a></p>
  <p>Can anyone tell me the exact solution? Please do tell me the specific solution with all the steps to do.</p>