Hi 

  Server : kamailio 4.0
  Configuration :Outbound with engage_media_proxy  (See the attachment )
  Shared Mem : 1024 MB
  Dialog TimeOut : 600 (Seconds)

  Problem : Dialog's are not cleared sometimes , So after sometime server is not responding , but plenty of  shared memory is available,
  56 MB only used out of 1024 MB , there is no out of memory error but server is not responding until restart the server , there is no error in    kamailio log also

After investigating long time , the problem is non confirmed dialog's are not cleared even dialog timeout
  
 Thanks 
Arunkumar