shmget EEXIST 17 : shared memory already exists

Hello, We use : Informix Dynamic Server Version 7.31.UC2A on a Siemens box : ReliantUNIX-Y 5.45 A1023 RM600 6/3072 R10000 About twice a month, our db server crashes with this error : shmget: [EEXIST][17]: key 52564801: shared memory already exists ----- 03:15:52 Checkpoint Completed: duration was 0 seconds. 03:17:53 Checkpoint Completed: duration was 0 seconds. 03:19:54 Checkpoint Completed: duration was 0 seconds. 03:21:08 shmget: [EEXIST][17]: key 52564801: shared memory already exists 03:21:08 mt_shm_init: can't create resident segment 03:21:13 Checkpoint Completed: duration was 0 seconds. 03:21:14 Informix Dynamic Server Stopped. ----- I think that something is wrong with shared memory configuration, but I can't see which parameter. (Our server have 3 GB RAM) >onstat -c | grep SHMSHMBASE 0x20000000 # Shared memory base address #SHMVIRTSIZE 8000 # initial virtual shared memory segment size #SHMVIRTSIZE 245760 # initial virtual shared memory segment size SHMVIRTSIZE 16000 SHMADD 8192 # Size of new shared memory segments (Kbytes) SHMTOTAL 0 # Total shared memory (Kbytes). 0=>unlimited Is there any way to avoid these crashes at night ? Can someone help me to better configure the shared memory ? Thanks in advance Ben