[strongSwan] How to limit the size of the filelog

[梅香]

Hi all,
I have followed the steps mentioned in wiki to create a filelog, but the filelog is too big so that run out of the memory. For example, I used an instrument to establish ipsec tunnels at the speed of 100 per second, the filelog soon reached 1.5G .
Following is my strongswan.conf:
charon 
{
  load =  openssl random x509 pubkey hmac xcbc stroke  kernel-pfkey  kernel-netlink  eap-radius  socket-default dhcp ha
  threads = 1000 
  ikesa_table_size = 2048 
  ikesa_table_segments = 128 
  half_open_timeout = 20 
  init_limit_half_open = 1000 
  cookie_threshold = 10000 
  plugins 
  {
     dhcp 
    {
      server = 10.2.6.255
    }
 }
  
  filelog 
  {
        /tmp/log/charon.log 
        {
            time_format = %b %e %T
            append = no
            default = 1
            flush_line = yes
        }
        stderr 
        {
            ike = -1
            knl = -1
            enc = -1
            net = -1
            tls = -1
            lib = -1
            # prepend connection name, simplifies grepping
            ike_name = yes
        }
    }
    syslog 
    {
        daemon 
        {
            default = -1
        }
        auth 
        {
            default = -1
            #ike = 0
        }
    }
}
I want to know how to limit the size of the filelog ?
Thank you for your help.
Yourth,
Anna