I've managed to install CentOS 6 on a 192MB virtual machine using LiveCD install-to-disk graphical method.
This is not normally possible because of: - hard-coded minimum supported memory in Anaconda installer - it will show a message "You do not have enough RAM to install CentOS Linux on this machine" if you try or force you to use seriously crippled text installer; - a bug in Anaconda installer, which prevents it from using swap during installation.
I think it would be useful to be able to install CentOS 6 (or Scientific Linux 6 or RedHat Enterprise Linux - RHEL 6) on low memory old computer or laptop, as it can be very capable firewall, home www server, proxy etc.
So the procedure is as follows:
1. Boot to 32-bit CentOS LiveCD (CentOS-6.0-i386-LiveCD.iso) in graphical mode (if you have at least 256MB RAM) or text mode (if you have less than 256MB RAM).
2. Login as root.
3. Edit a file /usr/sbin/anaconda - using vim in text mode or gedit in graphical mode - search for "within" and modify function "within_available_memory" adding a line "return True" like this: def within_available_memory(needed_ram): return True # kernel binary code estimate that is # not reported in MemTotal by /proc/meminfo epsilon = 15360 # 15 MB return needed_ram < (iutil.memInstalled() + epsilon) This would get rid of artificial hard-coded memory requirement.
4. Edit a file /usr/lib/anaconda/storage/__init__.py - search for 4th occurrence of "swapoff" and modify a fragment of function "umountFilesystems" from: for device in devices: if not device.format.mountable and \ (device.format.type != "swap" or swapoff): continue to: for device in devices: if not (device.format.mountable and \ (device.format.type != "swap" or swapoff)): continue (add parentheses - left one after "if not" and right one after "or swapoff"). This would fix a bug in installer.
5. Run "liveinst" which should start graphical installer.
6. During installation create swap partition so that you have at least 1GB of available memory (RAM+swap) (default setup should suffice, but I personally do not recommend it as it used LVM, which AFAIK prevents disks from using barriers).
The bug is reported upstream: https://bugzilla.redhat.com/show_bug.cgi?id=708966 but for Fedora Linux.
Regards Tometzky