db2audit.log is growing automatically

Hi,

In DB2 8.2, db2audit.log file grows automatically without executing flush command.

Is it because of zero size of audit buffer?
DB2 documentation states : When the size of the buffer is set to 0, synchronous log writing occurs, and the audit buffer is not used.

I executed "get dbm cfg" query that results to :
Audit buffer size (4KB) (AUDIT_BUF_SZ) = 0

Then I executed :
update dbm cfg using audit_buf_sz 10
db2stop
db2start
get dbm cfg :
Audit buffer size (4KB) (AUDIT_BUF_SZ) = 10

But still db2audit.log is growing automatically even I don't execute flush command.
What should I do to prevent db2audit.log from growing automatically???

Thanks in advance,
Roopsi