ok i searched on metalink with different terms and i got this...
Doc ID: 1060139.6
How to Clean-Up Entries in V$LOG_HISTORY and/or V$ARCHIVED_LOG:
The number of archived redo log files maintained in the controlfile and
available through V$LOG_HISTORY is determined by the MAXLOGHISTORY parameter of
the create database command. The archived redo log records are maintained up to
the value of MAXLOGHISTORY, then wraps and overwrites any previous entries starting
from the beginning.
Data stored in v$log_history table depends on maxloghistory parameter of controlfile. This parameter set during database creation or controlfile re-creation. Means if data would be more than it will overwrite and if you want to change value of same parameter and want to store more data in v$log_history then you should need to re-create controlfile.