Re: Considerations for lilo removal
Mike Hommey <firstname.lastname@example.org> writes:
> On Mon, Jun 16, 2008 at 02:27:11AM -0500, William Pitcock wrote:
>> On Mon, 2008-06-16 at 07:20 +0000, Sune Vuorela wrote:
>> > On 2008-06-16, William Pitcock <email@example.com> wrote:
>> > > That doesn't strike me as a valid configuration. Infact, it shouldn't
>> > > work with lilo because lilo wants /boot to be on a real device. The fact
>> > > that it does should be considered a bug, not a feature.
>> > lilo-22.8$ head debian/patches/01_devmapper.dpatch
>> > #! /bin/sh -e
>> > ##
>> > ## All lines beginning with `## DP:' are a description of the patch.
>> > ## DP: Patch to make lilo understand device-mapper block devices.
>> > ## DP: Bug#229932
>> That patch only makes lilo map LVMs to an appropriate physical device.
>> It does not guarantee that you will be able to boot off of an LV on a
>> physical volume. As such, the behaviour is still undefined.
>> Consider a situation where /boot spans multiple PVs, and you will see
>> lilo fail to boot the system correctly.
>> If /boot happens to be on a single PV, then it will work, but it is
>> still not guaranteed.
> Il will only work if all extents containing initramfs and kernel are
> contiguous and ordered on the physical volume.
Why? Lilo looks up the block addresses of the file on the disk. Having
the LV fragmented into several segments is no different from having
the file fragmented in the filesystem.
Having /boot be on a single PV, preferably the one with the bootblock
should be totally sufficient.