Root partition and LVM

[Timothy Murphy]

Mikkel L. Ellertson wrote:

>> The official LVM HOWTO <www.tldp.org/HOWTO/LVM-HOWTO/>
>> warns against including the root partition in the VG,
>> while the documents pointed to in the Wiki,
>> eg <http://people.redhat.com/agk/talks/>,
>> seem to assume that / will be included in the VG.
>> 
>> Is the information in the HOWTO out-of-date?
>> 
> What it says is:
> 
> root on LV should be used by advanced users only root on LVM
> requires an initrd image that activates the root LV. If a kernel is
> upgraded without building the necessary initrd image, that kernel
> will be unbootable. Newer distributions support lvm in their
> mkinitrd scripts as well as their packaged initrd images, so this
> becomes less of an issue over time.
> 
> 
> Because RedHat and Fedora build the initrd image for you, this is
> not an issue unless you are building your own kernel. Then again, if
> you are building your own kernel, you are probably an advanced user
> - at least to the point of knowing that you need to build a matching
> initrd image to take care of mounting the LVM root partition.

Thanks for the info.

I must say, the documentation on LVM under Fedora seems surprisingly sparse.

The official (tldp) HOWTO is very out-of-date,
and spends a disproportionate amount of time talking about LVM1
and kernel-2.4.*, eg of the 13 questions in the LVM2-FAQ,
7 are about the difference between LVM1 and LVM2.

Also about half the HOWTO is taken up with compilation of LVM,
although I would imagine 95% of Linux users now
start from a distribution, which will presumably include LVM.

But enough whinging.
Can I create my LVM "partitions" before installing FC-5?
Or do I have to leave this to the installation?
I'd like to decide for myself what partitions to have,
and what size they are, if that is possible.

Is there an account somewhere of how precisely to do this?
(I mean the actual commands I have to give,
rather than an essay on the philosophy of LVM.)



-- 
Timothy Murphy  
e-mail (<80k only): tim /at/ birdsnest.maths.tcd.ie
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland