Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Performance Tuning Guide


To increase the shared memory to 512 MB, run the following commands:

echo 536870912 > /proc/sys/kernel/shmmax
echo 536870912 > /proc/sys/kernel/shmall

Where the file shmmax contains the maximum size of a single shared memory segment, and shmall contains the total shared memory to be made available.

This value is large enough for a standard HADB node that uses default values. If the default values are changed, consider changing these values, as well.

To make these changes permanent, add those lines to /etc/rc.local on your Linux machine. With Redhat Linux, you can also modify sysctl.conf to set the kernel parameters.