dump transaction...with no_log truncates the log without logging the dump transaction event. Because it copies no data, it requires only the name of the database.
Every use of dump transaction...with no_log is considered an error and is recorded in the SAP ASE error log.
If you have created your databases with log segments on a separate device from data segments, written a last-chance threshold procedure that dumps your transaction log often enough, and allocated enough space to your log and database, you should not have to use with no_log. If you must use with no_log, increase the frequency of your dumps and the amount of log space.