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This document describes how to create and install an initrd, which is  
required to use with the kernel. Also see "man mkinitrd".

1. What is an initrd?
2. Why to I need an initrd?
3. How do I build the initrd?
4. Now that I've built an initrd, how do I use it?

1. What is an initrd?

Initrd or "initial ramdisk" is a very small Linux filesystem that is loaded 
into memory and mounted as the kernel boots, and before the main 
root filesystem is mounted.

2. Why do I need an initrd?

The usual reason to use an initrd is because you need to load kernel 
modules before mounting the root partition. Usually these modules are 
required to support the filesystem used by the root partition (ext3, ext4,
btrfs, xfs), or perhaps the controller that the hard drive is attached 
to (SCSI, RAID, etc). 

3. How do I build the initrd?

The easiest way to make the initrd is to use the mkinitrd script included 
in the mkinitrd package found in nakshatra64/a directory.

First, make sure the kernel, kernel modules, and mkinitrd package are 
installed.

Example: 
#  installpkg kernel-6.6.18-x86_64-1.txz
#  installpkg kernel-modules-6.6.18-x86_64-1.txz
#  installpkg mkinitrd-1.4.11-x86_64-28.txz

Change into the /boot directory.

  cd /boot

Now run mkinitrd.
For example : 

# mkinitrd -k 6.6.18 -m ext4 -f ext4 -r /dev/sdb3 -o initramfs-6.6.18-x86_64.img

where , -k = kernel version
	     -m = colon seperated values of modules list to be built into the initrd
	     -r = root device  
	     -f = filesystem of the root device (ext4)
	     -o = output file 

This will build a initramfs-6.6.18-x86_64.img.

For more details on mkinitrd check its man page.

In case of a LVM setup for the disks the mkinitrd command will include 
the -L flag.

eg : mkinitrd -k 6.6.18 -m ext4 -f ext4 -r /dev/<vgname>/<lvname> -L -o <output file>

And finally in case of a RAID setup , mkinitrd will need the -R flag.
eg: mkinitrd -k 6.6.18 -R -o /boot/initramfs-6.6.18-x86_64.img

4. Now that I've built an initrd, how do I use it?

Once you have your initrd file, simply run :
# grub-mkconfig -o /boot/grub/grub.cfg

The GRUB bootloader will pick it up along with its corresponding 
kernel.
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Note : The output of the above grub command will clearly indicate 
that the detected initramfs-<kernel-version>-arch.img is a initrd file.

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-- Team Nakshatra