Problems with shared memory to communicate between two Linux tasks

docrudolph This has nothing to do with your problem, I expect, but I am running an up to date release of RHEL 3, and it is using kernel 2.4.21-32.0.1.ELsmp. You cannot really give a kernel and expect people to know what release of what distribution you are using.

I do infer you are running an outdated kernel, and perhaps your distribution is not up to date either. But usually, while that can give security problems, I doubt it is giving you the problems you are experiencing.

I run shared memory applications, especially IBM DB2 V8.1.7, and I had to diddle fileetc-sysctl.conf to get a few more resources for it. The relevant part of my file is:

# Controls shared memory, messages, semaphors, and max open files for IBM DB2 # These added by jdbeyer. # shmmax is (max shared seg size (bytes)) # Use up to half the memory if needed; we have lots. But 1GB max. #kernel.shmmax=268435456 kernel.shmmax=536870912 # Default msgmni (max # of msg queue identifiers) was 16: not enough. kernel.msgmni=1024 # Last item was 128: we raise to 1024. # Guessing these items are, in order: # max num of semaphores per id: 8000 MAX # semaphore maximum value: 32767 MAX # max num of ops per semop call: 1000 MAX # max # of semaphore identifiers: IPCMNI MAX (32767) kernel.sem=250 32000 32 1024 # We need at least 8192: default is 432537, so this one commented out. #fs.filemax=8192

-- .~. Jean-David Beyer Registered Linux User 85642. V PGP-Key: 9A2FC99A Registered Machine 241939. ^^-^^ 09:40:00 up 13 days, 3:30, 4 users, load average: 4.56, 4.37, 4.28