DB2 - Archive Mode - on what values to set LOGPRIMARY,LOGSECOND,LOGFILSIZ?
LOGPRIMARY, LOGSECOND and LOGFILSIZ combine to define the maximum size of the transaction log on your server using the following formula:

Total Size = (LOGPRIMARY + LOGSECOND) * LOGFILSIZ * 4096 bytes


In your case, this results in (13 + 15) * 4096 * 4096 = 469762048 bytes.

The maximum transaction log size limits 2 things:

1) the absolute size of a single transaction
2) the "timespan" between the oldest active transaction and the newest transaction.

You need to make it large enough to handle both scenarios, although if you're running into problems relating to #2 then you really have a problem with a poorly-behaved app that isn't committing.

Choosing an appropriate value for LOGFILSIZ should be based on how regularly you want to archive log files, as this will have an effect on your recoverability in the event of a problem.  If your database archives log files only once every hour (or less), you will potentially lose much more data in the event of a serious problem than if your database archives a log file every 2-3 minutes (because every time a log file is archived it should be copied to NetBackup).