2-3 minutes for a peak-hours doesn't seem to frequent to me. What's the log-switch interval during normal load? Do you have any complaints about "checkpoint not complete" or "archiving not be fast enough" in your alert log?
If you realy want to set a redo log so big (500M or 1G) I'd advise you to perform a couple of explicit checkpoints during filling of your online log (set LOG_CHECKPOINT_INTERVAL and/or LOG_CHECKPOINT_TIMEOUT properly). If you do not do so you'll potentially face two problems:
1. In case you loose all members of your active logfile group you'll loose quite a big amount of data (1G worth of transactions).
2. In case your database crashes or your performs shutdown abort your instance recovery after restart might take quite a long time.
Jurij Modic
ASCII a stupid question, get a stupid ANSI
24 hours in a day .... 24 beer in a case .... coincidence?