This parameter allows you to specify the number of primary log files to be preallocated. The primary log files establish a fixed amount of storage allocated to the recovery log files.
Under circular logging, the primary logs are used repeatedly in sequence. That is, when a log is full, the next primary log in the sequence is used if it is available. A log is considered available if all units of work with log records in it have been committed or rolled-back. If the next primary log in sequence is not available, then a secondary log is allocated and used. Additional secondary logs are allocated and used until the next primary log in the sequence becomes available or the limit imposed by the logsecond parameter is reached. These secondary log files are dynamically deallocated as they are no longer needed by the database manager.
Recommendation: The value chosen for this parameter depends on a number of factors, including the type of logging being used, the size of the log files, and the type of processing environment (for example, length of transactions and frequency of commits).
Increasing this value will increase the disk requirements for the logs because the primary log files are preallocated during the very first connection to the database.
If you find that secondary log files are frequently being allocated, you might be able to improve system performance by increasing the log file size (logfilsiz) or by increasing the number of primary log files.
For databases that are not frequently accessed, in order to save disk storage, set the parameter to 2. For databases enabled for rollforward recovery, set the parameter larger to avoid the additional processing time of allocating new logs almost immediately.