Re: Shared Memory Tuning

"Andrew J. Saville" <Andrew.Saville@bridge.bellsouth.com> wrote: >Does anybody out there know why Online 7.1 reserves 99% of swap space on >our HP9000/K400 running HPUX 10.01. We have 640 mb of ram and over 600 >mb of swap. The shmax parameter is set to it's highest setting possible. > I don't have my notes with me, but it is something like 0x4000000. >This swap reservation causes other processes not to be able to start. >Buffers in informix are set to 60,000. This was 100,000 but had to be >reduces to start other processes. This seems to be the only informix >parameter that affects this swap reservation. James, I don't think that this is necessarily Informix reserving the swap space but rather the OS reserving the swap space for each oninit process that is started. There is a certain amount of swap space that is reserved by the OS for each process running on the box. The swap space size is based on the data size, something call bss(block started by symbol size) and shared memory size. I don't think swap space for the text portion of a process is reserved. Anyway as far as Informix, shared memory is going to be the largest part of the oninit process and that is why by reducing the largest user of shared memory, the buffers, helped you in this case. I think if you increased your swap space size which is normally 2-3 times real memory, you should be able to have all processes running that need to run at the same time. -- Melvin Mariney, Informix DBA e-mail: melvin.mariney2@bridge.bellsouth.com