Gentoo Archives: gentoo-dev

From: Rich Freeman <rich0@g.o>
To: gentoo-dev@l.g.o
Subject: Re: [gentoo-dev] Re: udev and /usr
Date: Sat, 17 Sep 2011 15:04:41
In Reply to: Re: [gentoo-dev] Re: udev and /usr by Joost Roeleveld
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 is back up... Rich