On Informix Virtual Segments - SHMADD/SHMVIRTSIZE

Can anyone help shedding some light on the following issue. Informix IBM tech is saying one thing while IBM AIX tech contradicts its counterpart. I have one IDS instance on AIX 5.2 and the Informix ver is 7.31.UD7 , 32bit SHMVIRTSISE set to 1100000 SHMADD set to 100000 BUFFERS set to 200000 SHMTOTAL set to 0Physical Memory of Box is 8GB The total instance size is about 2GB or 1.94GB (1944016) One day the instance try to add segments to support the workload. It added one successfully and about 1 hour later it hung and finally went down while trying to add another segment with the following MSG. shmat: [EMFILE][24]: out of shared memory segments, check system SHMSEG shmdt: errno = 22