oracle archive log history

Have you ever measured the amount of changes you have in your database. Sometimes it can be a good idea to know. Maybe you need to set up a standby database and you need details about the traffic between the two system. Or maybe you plan to move  the primary database and need to evaluate the different options. This will vary quite a bit from day to day, but one query that level this out on a monthly basis can be as shown below.

Multiply the count with the average size of your archive logs and you will have an idea.

Now may also be a good time to evaluate the number of log switches you have in your database. Every minute is too frequent. Every 10 minute to every hour is a more optimal configuration. Consider to resize the log files (ie create a new set of logfiles and disable the old ones) if you are far off.

select to_char(first_time, 'yyyy-mm'), count(*)
  from V$log_history
  group by to_char(first_time, 'yyyy-mm')
  order by 1;