Sun GlassFish Enterprise Server 2.1 High Availability Administration Guide

ProcedureTo configure shared memory on Linux

On Linux, you must configure shared memory settings. You do not need to adjust the default semaphore settings.

  1. Log in as root.

  2. Edit the file /etc/sysctl.conf.

    With Redhat Linux, you can also modify sysctl.conf to set the kernel parameters.

  3. Set the values of kernel.shmax and kernel.shmall, as follows:

    echo MemSize > /proc/sys/shmmax
    echo MemSize > /proc/sys/shmall

    where MemSize is the number of bytes.

    The kernel.shmax parameter defines the maximum size in bytes for a shared memory segment. The kernel.shmall parameter sets the total amount of shared memory in pages that can be used at one time on the system. Set the value of both of these parameters to the amount physical memory on the machine. Specify the value as a decimal number of bytes.

    For example, to set both values to 2GB, use the following:

    echo 2147483648 > /proc/sys/kernel/shmmax
    echo 2147483648 > /proc/sys/kernel/shmall
  4. Reboot the machine using this command:

    sync; sync; reboot