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

Feuerbacher, Alan AFeuerbacher at ALLEGROMICRO.com
Mon Nov 5 14:11:15 PST 2012


Philippe Delavalade wrote:

> > Set up the partitions like this, using an ext4 filesystem:
> >
> > /dev/sda1   /boot                      100M
> > /dev/sda2   Extended Linux partition   ~100G
> > /dev/sda5   Linux swap                   2G
> > /dev/sda6   /                          ~98G

> This seems odd to me. Maybe I'm wrong but your swap seems too small for
> your 16GB of RAM

Various people had various suggestions. Bruce suggested 2G, and gave me a link to an article that suggested somewhere between 0 and 32G. :-)

> and you told you have a Fedora on sdb2, so swap is
> certainly on that drive (i don't know about fedora but I can't imagine
> there's no swap on sdb).

I want the LFS installation to be completely independent of the host system. I'm considering the host system merely as a vehicle to install LFS.

> The boot partition is not required ;

Yes, but section 2.2.1.3 highly recommends it.

> you've
> already a boot partition or directory on sdb. What do you plane to put
> on your extended
> sda2 ?

I don't know yet. This is mainly a learning expedition now. Also, I'm trying to stick as closely as possible to the LFS book. Bruce gets testy if you don't do that, you see. :-)

> Following the lfs book, you just need one partition ; you can have a
> /usr partition if you like and a var one and a tmp one, etc. It's your
> first built and, maybe I'm wrong, but you'll certainly not work with
> lfs for this first time, perhaps later...

You mean I'm going to do all this more than once? :-)

> As to me, I built lfs many
> times but I never continue whith blfs ; debian is my work system ; lfs
> is just to learn and undertand more deeply a lot of things.

I see. Well, I'm too ignorant yet to know what I'll end up doing. But I'm with you on the learning part. That's why I'm doing this.

> > Use mke2fs -t ext4 to create filesystems on /dev/sda1 and /dev/sda6.
> 
> Ext4 seems inapropriate for your little boot partition. IMHO use ext2.

The LFS book suggests ext3 and some people today have suggested ext4.

> > I should NOT use mke2fs to create filesystems on /dev/sda2 and
> > /dev/sda5. I don't fully understand why not, though. Can someone
> explain?
> 
> On the swap partition, you'll don't write anything ; this partition is
> used by the system as a memory when your ram is unsufficient.

Ok. So is swap not considered a filesystem by convention, or for some other reason?

> > Under the above scheme, the extended linux partition CONTAINS the
> swap
> > and / logical partitions, so it seems reasonable that you would not
> > use mke2fs both on it, and on the partitions it contains, right?
> 
> sda2 doesn't contain0 sda5 and sda6. You've misunderstood something (or
> it's me :-) ).

I'm probably using the wrong terminology, but I meant "contain" in the sense that fdisk displays the sector numbers of sda5 and sda6 as "inside" the sector numbers of sda2.

> > And why would you
> > not make a filesystem on sda2, thereby (in my naive brain, anyway)
> not
> > having to make a filesystem on sda6? Further, why would you not make
> > the whole drive -- /dev/sda -- one filesystem?
> 
> sda is too big ; you are obliged to make a partition on it.

Too big? The drive I'm going to use here is a new 3TB one I bought on sale a few days ago. The SSD I was using until now is 256GB. And no matter how big a drive is, you still have to make one or more partitions on it, right?

Or are you thinking in terms of making partitions of, say, 100GB each for different spins of various distros and LFS?

> If you consider an usb stick, if it is a litte one, it will be on sdf
> (for
> instance) but if it is more thant 2GB (I'm not sure for the size) it
> will be on sdf1. I don't know why but it is so :-)

I've never used a usb stick in a linux system. But what you describe sounds a bit odd.

> > The man page for mke2fs talks about making filesystems in disk
> > partitions. So a filesystem in the general sense can contain one or
> > more filesystems in the mke2fs sense, and it's not always clear to me
> > (again, a newbie to this stuff) which one is being talked about. I
> > suppose experience will take care of that.
> 
> I don't really understand what you mean, sorry :-)

The IBM article defined a filesystem as an organized set of data. That's a very general definition. That's quite different from the very specific notion of a "filesystem" as used in the mke2fs man page.

> Hope this can help but was I clear enough ?

You've helped a lot, thank you very much!

Alan



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