I have a secondary mail server setup and over the weekend a runaway database process spiked our server and hung Postfix from Friday until we rebooted Monday morning. I kind of expected any mail that was missed on the primary mail server to be stored on the secondary and forwarded when the primary came back up. However, many of my client's emails have not shown up by today, Wednesday. Is there a way to check if they are still sitting on the secondary server? I logged into Webmin on it and looked at the Postfix queue, and it is empty. Is there anything else I can check?
Also, is there a flaw in the configuration or am I expecting something it does not do?