Sometimes, the kernel does not recognize all of your memory (RAM). You can check this with the
cat /proc/meminfo command.
Verify that the displayed quantity is the same as the known amount of RAM in your system. If they are not equal, add the following line to the
Replace xx with the amount of RAM you have in megabytes.
/boot/grub/grub.conf, the above example would look similar to the following:
# NOTICE: You have a /boot partition. This means that
# all kernel paths are relative to /boot/
title Red Hat Enterprise Linux Client (126.96.36.199.el6.i686)
kernel /vmlinuz-(188.8.131.52.el6.i686 ro root=UUID=04a07c13-e6bf-6d5a-b207-002689545705 mem=1024M
Once you reboot, the changes made to
grub.conf are reflected on your system.
Once you have loaded the GRUB boot screen, type
e for edit. You are presented with a list of items in the configuration file for the boot label you have selected.
Choose the line that starts with
kernel and type
e to edit this boot entry.
At the end of the
kernel line, add
where xx equals the amount of RAM in your system.
Press Enter to exit edit mode.
Once the boot loader screen has returned, type
b to boot the system.
Remember to replace xx with the amount of RAM in your system. Press Enter to boot.