Shared Memory question

[YCL]

Dear all,

We have several RH 6.1 boxex running as Sybase and Oracle servers. How do I increase the shared memory under RH6.1? What is the command or GUI utility? Someone at work mentioned about modifying the kernel parameter file /proc/sys/kernel/shmmax. Is this the correct approach?

thanks for any info or directions on how to accomplish this task.

-ycl

 

[Tardigrade]

Indeed it is.

To set the shared memory to nnn bytes type:

# echo nnn > /proc/sys/kernel/shmmax

To run both Oracle and Sybase i'd imagine you'd want it set pretty high! I know Sybase is very memory intensive.

Once you've got it set to a value you like add the line to your /etc/rc.d/rc.local file so that the settings are sorted out at boot time. ie stick the follwoing add the bottom...

echo -n "Setting shared memory..."
echo nnn > /proc/sys/kernel/shmmax
echo "Done."


--
Scott

 

[YCL]

Great. Thanks for the confirmation.

Do I need to reboot after setting the shmmax file? I did an:

echo 80000000 > /proc/sys/kernel/shmmax

to set the max shared memory to 80MB, but the output of "free" did not reflect the changes. Is a reboot necessary?

I also know of another way of setting shmmax which involves modifying and recompiling the kernel, but I was too chicken to try that at the moment.

Thanks.

-ycl