The Linux 2.4 kernel changes the default values of some ipc
limits. However, the default value for the msgmni is
16, which causes difficulties running DB2 with the
default 2.4 kernel ipc parameters.
Fortunately, the 2.4 kernel also enables you to change a number
of these parameters through the /proc
filesystem. With the 2.4 kernel, you do not have to recompile your kernel to
experiment with different parameter values.
Configure the msgmni parameter by issuing the
sysctl command as root:
bash# sysctl -w kernel.msgmni=128
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You can also change values directly in
/proc/sys/kernel using the
echo command:
bash# echo "128" > /proc/sys/kernel/msgmni
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To set the msgmni kernel parameter at boot time, append the
following lines to /etc/sysctl.conf:
# Sets maximum number of message queues to 128
# Set this to 1024 or higher on production systems
kernel.msgmni = 128
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To check the current
ipc settings, issue the
ipcs -l command:
bash$ ipcs -l
------ Shared Memory Limits --------
max number of segments = 4096
max seg size (kbytes) = 32768
max total shared memory (kbytes) = 8388608
min seg size (bytes) = 1
------ Semaphore Limits --------
max number of arrays = 128
max semaphores per array = 250
max semaphores system wide = 32000
max ops per semop call = 32
semaphore max value = 32767
------ Messages: Limits --------
max queues system wide = 128
max size of message (bytes) = 8192
default max size of queue (bytes) = 16384
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