From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <39355918.C2B6A94B@msede.com> Date: Wed, 31 May 2000 20:25:28 +0200 From: Michael Marxmeier MIME-Version: 1.0 Subject: Re: [linux-lvm] SuSE/LVM boot problem References: <390FD771.DB59EECB@msede.com> <20000503095326.A4439@archimedes.suse.com> <20000531110128.A22796@gruyere.muc.suse.de> <12xB7E-0izhAGC@fwd05.sul.t-online.de> <20000531181803.A30169@gruyere.muc.suse.de> Content-Transfer-Encoding: 7bit Sender: owner-linux-lvm Errors-To: owner-linux-lvm List-Id: Content-Type: text/plain; charset="us-ascii" To: Andi Kleen Cc: Christoph Hellwig , adilger@turbolabs.com, linux-lvm@msede.com Andi Kleen wrote: > > On Wed, May 31, 2000 at 06:13:08PM +0200, Christoph Hellwig wrote: > > Andi Kleen schrieb: > > > > > > > > - lilo needs to understand about lvm and use the lvm provided ways to > > > > get physical mappings. > > > > > > That's complicated. Someone did a similar hack for RAID0, but LVM is more > > > complicated than MD RAID0. Better just supply the real block numbers to lilo > > > and rerun it as needed (LVM could warn about it) > > > > Don't use lilo, use grub. I'm trying to implement lvm support in grub. The idea > > is that grub should read the first lvm on each pv. This first lv must be only on > > this pv. (and have a special name, eg lv_root, so grub can find it) > > Limiting to the ``first LV'' sounds ugly. When you read the first, is it > that hard to read the second (and allow arbitary names) ? You need to distinguish 'bootable' LV from others. This could either be by LV name or a 'bootable' flag. However if we need a flag anyway and could accept the restriction to have to root fs contigous on a single PV and non striped we could simply save the starting block and size as well. This is not that different from a partition. For example HP-UX has a simple hack in the boot area which holds the start and size of the /stand fs such that the boot loader and the kernel could simply handle this as a partition equivalent during boot. It should be possible to detect this 'bootable' flag and the start/size in the LVM init code without causing much kernel bloat and create the equivalent of a partition using a fixed major/minor. vgscan could then in user space create the device files accordingly such that the major/minor of the LV holding the root fs is mapped accordingly. AFAIR someone already did something similar by hacking the partition table and creating an overlapping partition which just happened to map to the root LV. Michael -- Michael Marxmeier Marxmeier Software AG E-Mail: mike@msede.com Besenbruchstrasse 9 Phone : +49 202 2431440 42285 Wuppertal, Germany Fax : +49 202 2431420 http://www.msede.com/