[Discuss] Limiting amount of memory

[Tim Callaghan]

I'm trying to reduce the amount of available memory on a Dell R710.  It has
48GB installed, I want to be able to boot it with 8G and 16G for some of my
benchmarks.

I've modified my /etc/grub.conf file, copying the top section and adding to
the end of the kernel line as follows:

kernel /boot/vmlinuz-2.6.18-348.3.1.el5 ro root=LABEL=/ mem=8G


My problem is that with the "mem=8G" option, "free -g" reports 6G.  With
mem=16G, "free -g" reports 9G.

What am I missing?

Thanks in advance,

Tim