If you, like me, find that you are struggling with all the Cisco nutty details that you are required to learn from heart for your exam, then of course having a mnemonic can help you achieve just that. So I came up with a ridiculous mnemonic to remember the SYSLOG levels in the right order:
Eat Apple Cider Even When Not in Dublin
Eat -> Emergency (0)
Apple -> Alert (1)
Cider -> Critical (2)
Even -> Error (3)
When -> Warning (4)
Not -> Notification (5)
In -> Information (6)
Dublin -> Debug (7)
I know its a ridiculous sentence and you do not EAT cider, but as i lived in Ireland for a while, i could not resist the urge to refer to it.
I hope it can help you memorizing trivia like this.