Dynamic log allocation prevents log files from filling and hanging the system during long transaction rollbacks. The only time that this feature becomes active is when the next log file contains an open transaction. (A transaction is long if it is not committed or rolled back when it reaches the long-transaction high-watermark.)
The database server automatically (dynamically) allocates a log file after the current log file when the next log file contains an open transaction. Dynamic log allocation allows you to do the following actions:
The best way to test dynamic log allocation is to produce a transaction that spans all the log files and then use onstat -l to check for newly added log files. For more information, see Allocating Log Files.