i search infocenter of Ibm Db2 for backing up the transaction log but i can't figure out. using Tivoli Storage manager software is an option for back up i learned from infocenter. but how can i back up the transaction logs without TSM software
By default DB2 does not archive its active log files. Because these transaction log files contain active information, it's not necessarily useful to back them up (just like it's not useful to back up the database data files while the database is running...).
However, if you have enabled log archiving (which enables point-in-time recovery, and works by moving "full" transaction logs from the active log path to another destination), DB2 supports a number of different destinations, including local disk, TSM and other storage managers (NetBackup, Legato, etc).
See documentation on the LOGARCHMETH1 database configuration parameter for more details.