I am starting to build a LFS system.

Right now I'm on a Red Hat 7.2 system. What I want to do is add another HDD to my system (as a primary IDE slave), and then install LFS on that seperate HDD.

The LFS instuction indicates that I need a native linux partition to install on, but it doesn't say anything about adding a virtual memory parition or a /boot partition. How is my LFS HDD going to boot with only a /root partition?

you don't ever *need* a /boot partition you only need a primary partition on the drive which contains the kernel image. as windows is gay most distros install the system inside an extended partition, which isn't bootable and so a single small partition for /boot is created as primary to let the system boot ok. It also helps with that good old lilo 1024 cyl issue

a single / partition will work fine. As to swap you have two options:

1) you can create a swap partition on that second harddisk.

2) you can use the same swap partition as your Redhat distribution uses.

If the second harddrive stays in that system it'll really be a waste of space to create a seperate swap partition for use with LFS. It is of no consequence to use redhat's swap partition.

Ok. So I can just use the swap partition from redhat. But what about booting? On my Red Hat hard drive, I have grub installed on the boot sector. If I want to boot LFS, how does that work? Or is that covered in the instructions down the road?

What if I want to remove my primary hard disk (the one with redhat) and just make the LFS disk my primary? Then I'll need some sort of swap partition and a /boot partition also. Does the LFS instructions cover this?

Grub isn't covered by the lfs-book yet. As long as Grub isn't marked stable by the GNU guys, the book won't use it. Personally I love it and I use it everywhere but a policy I put in place is no unstable software in the book. So for now only Lilo is dealt with.

But, I invite you to subscribe to the blfs-support mailinglist. A lot of people there will be able to help you setting up Grub. Info on mailing lists (which ones to use, how to subscribe) can be found via http://linuxfromscratch.org/mailinglists/info.shtml

If you remove the primary harddrive, then yes you need to create a swap partition on that second drive of yours.

A boot partition is not necessary. It might be handy to have one so you can share the kernel images between different Linux systems, but it's not mandatory. Just like creating a seperate /usr /home or /var partition isn't mandatory (though it is advisable, but /boot is strictly a user preference. If you have the need to share kernel images, then create a seperate partition. If not, don't bother)

Why is it advised to create a seperate disk partition for /usr /home and /var?

Since I want to be able to remove my primary Red Hat disk, and just run my LFS disk by itself, I'm going to go ahead and partition it accordingly. I'm going to make a 16MB /boot partition, a 1024MB swap partition, and the rest as my root "/" partition. That sounds good right?

1024 MB is a bit much for swap for normal day-to-day use. I have 128 MB and it's hardly ever used.

Why advisable to have seperate /usr /home /var partitions. A few reasons

1) if something goes wrong on a partition, it doesn't damage all your data and you can still boot the system.

2) if sometimes goes wrong with a program and it starts filling up say /var/spool it won't fill your entire disk (and it'll take a lot less time to fill up, then probably crash)

It's mostly used for servers than for workstations. If you're the only user on your system, there's not much reason for creating seperate partitions, but the "if something goes wrong, not everything is gone" still holds true. Unless your harddisk itself gets damaged, but you can do very little against that.

Another reason can be to share data. I use my /home partition on various Linux systems so no matter where I"m booted into, I have my /home/gerard directory always available.

I would dare say that you will never need 1024 MB of swap space. Unless you have a very good reason (and believe me, if you need the space you'll know what constitutes a "very good reason") you should not really need more than 256 MB, ever.

Ok thanks, I didn't know how much I needed, so I figured having too much was better than not enough

But besides that, is it going to work for me to create my secondary hard drive as a stand-alone LFS system?

shouldn't be a problem. Keep in mind when constructing lilo/grub and /etc/fstab that if when you move the second harddisk to primary at some point, you need to update all hdb (or hdb or hdd) references to hda, and in grub it would be disk0 instead of disk1/2/3