[lfs-support] What Is "The" LFS Partition?

Bruce Dubbs bruce.dubbs at gmail.com
Mon Nov 5 09:14:13 PST 2012


Feuerbacher, Alan wrote:
> Philippe Delavalade wrote:
>
>>> I read the man page for mke2fs and it's as clear as mud. And the
>>> LFS book is completely unclear about exactly what is going on.
>>
>> The book suppose that you have some knowledge about linux and
>> partitions :-)
>
> Well I do have *some* knowledge. It's just a matter of how much. :-)
>
> Seriously, I'm doing this in order to learn about all this stuff.
>
>> And the man about mke2fs is not so unclear, as I can remember.
>
> It is to me. I'll have to think a lot more about what you and Bruce
> have told me, in terms of the mke2fs man page, and try to understand
> what I'm missing.
>
>>> Are you saying that I have to run mke2fs for EACH of the devices
>> /dev/sda1, /dev/sda2 and so forth?
>>
>> You'll have to do it for /dev/sda6 and for /dev/sda7 ; on sda2, I
>> think you plane to install your home and that can wait ; for
>> /dev/sda1 I think you can wait still the installation of the
>> bootloader ; and /dev/sda5 is the swap, you'll see what to do with
>> it at the end of your current section.
>
> My plan WAS to have /dev/sda1 as the /boot partition, and the rest as
> whatever fdisk forces you to have. After some experimentation and
> absorbing the material in the LFS book, I hit on this:
>
> /dev/sda1     /boot    500M
 > /dev/sda2     extended partition containing everything else
> /dev/sda5     swap 32G (I have 16G of RAM)
 > /dev/sda6     /usr /dev/sda7
 > /opt and so forth, following the LFS book.

/boot of 500M is a little large.  I normally use 100M, but it probably 
doesn't matter.

For a first build, do not use a separate /usr.  Don't open yourself to 
potential problems until you understand more.

You do not need 32G of swap.  That 2x RAM rule is obsolete.

http://askubuntu.com/questions/49109/i-have-16gb-ram-do-i-need-32gb-swap

I suggest 2G swap.  You can always add more later.

If you are going to use a MSDOS partition table, why skip 2 parimary 
partitions?  It really doesn't matter that much though.

> Questions:
>
> Why would I NOT use mke2fs immediately to make filesystems on sda1,
> sda2 and sda5? I want to know enough to really understand what is
> going on sufficiently that I could teach it to my grandmother. :-)

You can do it whenever you like.

> Why would I wait until the installation of the bootloader? Wait for
> what?

I think the idea was to put off the decision until you actually needed 
to install something on the partition.  It really doesn't matter though.

>> Anyway, there is certainly a swap partition on your host system.
>
> Yes, but what does that have to do with the LFS system?

All systems can share the same swap space.  It actually makes some sense 
to have the swap partition on a different drive for marginally improved 
performance (but you really don't want to use swap anyway, just have it 
available if absolutely needed).

> Ok, then: how does one get that information from the man page on
> mke2fs?

Man pages are not meant as a primary learning tool.  They are supposed 
to be quick references for options, etc.

"mke2fs  is  used  to create an ext2, ext3, or ext4 filesystem, usually 
in a disk partition."

What part do you not understand?

> OK, but the LFS book clearly says that every partition will be ext3.

In Section 3.3 it says "Instructions for creating other file systems can 
be found at 
http://www.linuxfromscratch.org/blfs/view/svn/postlfs/filesystems.html." 
  ext3 is just used as the primary example.

If you don't know why you want to deviate from the book, don't.

   -- Bruce






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