SHMBASE 0x44000000

Hi All, Redhat EL-AS3.0 Informix IDS 10.00.UC3 Physical Memory 8 GB OLTP One of our production server has got 3 instances (Live, Test and Test2). I know its not a good option to have test/dev instances on production server. You are right, eventually production server will have only Live instance. Hoping !!! My understanding about SHMBASE addressing is very poor. Sorry about that. I need to allocate SHMVIRTSIZE about 2.0 GB to Live instance and 750 MB each to Test and Test2. SHMTOTAL will be 0 for live and 1024000 for Test and Test2. Currently Live instance SHMVIRTSIZE is 900000 and SHMVIRTSIZE 300000 for other instances. SHMBASE for all three instances is 0x44000000. onstat - shows 1338012 Kbytes for Live and 732596 Kbytes for Test and Test2. Also /etc/syscntl has kernel.shmmax=1073741824 I need an advise on: 1. SHMBASE 0x44000000 is ok for all three instances ? If not, what is recommendation for Live, Test & Test2 SHMBASE ? 2. What should be optimal value for kernel.shmmax as current value will surely insufficient for Live to start ? Thanks in advance.