Re: [gentoo-dev] Re: udev and /usr

[Rich Freeman]

On Sat, Sep 17, 2011 at 2:16 AM, Joost Roeleveld <joost@××××××××.org> wrote:

>
> Except that Redhat and Centos use LVM by default. Which will also mean that
> "simple users" also end up using LVM.
> Then again, they also end up with an initr* and a generic kernel for
> everything under the sun.
> I haven't properly looked at the kernel-configs from redhat lately, but I
> don't think they include all the possible hardware options be default?
>
>
>
The typical mainstream binary distro approach is to:

1.  Build every module under the sun that won't cause more support headaches
than benefits.
2.  Build a really smart initramfs that can find root whether it is on raid,
lvm, luks, or on a SAN behind luks and a VPN (ok, I'm stretching it a
little).
3.  Deploy that on everything.

With an initramfs you can essentially build a completely modular kernel,
since the kernel can rely on any module it wishes right from the start.
 However, once the initramfs is done the kernel is still a minimal size
since unused modules don't occupy space (the initramfs wipes itself out of
ram as its last step, unless in a debug mode).

Sure, the fancy initramfs takes work, but since the install image is
one-size-fits-all it is less maintenance in the long haul.  Plus you can
replace your motherboard and still boot the same drive image.  The downside
is that it might take an extra second or two to boot, but dracut is pretty
fast.

Honestly, if I were running a server setup I'd probably consider using an
intiramfs.  They're a lot less susceptible to being messed up if for
whatever reason the drives get re-ordered in the BIOS (root=UUID, or with
LVM the device names can usually be trusted).  I once booted off of a rescue
CD that for whatever reason changed the major numbers assigned to my raid
devices and for a while I could never predict what /dev/md# my root would
end up with.  That is what started my quest to get dracut working, which
I'll continue whenever git.kernel.org is back up...

Rich