Press and hold the F5 key on your keyboard for 2 minutes while on gmail.com. You will get a "service unavailable" error. About 500 other people whose data happens to be cohosted with you will also get the same error, and all of you will be unable to send or receive email, even by IMAP, for about 10 mins while your particular corner of the data store is restarted and the data integrity checked.
Press and hold the F5 key on your keyboard for 2 minutes while on gmail.com. You will get a "service unavailable" error. About 500 other people whose data happens to be cohosted with you will also get the same error, and all of you will be unable to send or receive email, even by IMAP, for about 10 mins while your particular corner of the data store is restarted and the data integrity checked.
That doesn't happen on Google.com