Package: lvm10
Version: 1.0.8-8
Severity: critical
Problem description:
lvm10 is the logical volume manager userspace utility package for the
official 2.4 kernel series. When setting up a system which has its root
partition on LVM, the kernel has to be loaded from a non-LVM boot
partition (which the bootloader can handle), together with an initrd that
contains
/sbin/vgscan
/sbin/vgchange -a y
in its linuxrc to detect and initialize the LVM partitions. Only after
this, / can be moved to LVM.
the lvmcreate_initrd utility is supposed to create a ramdisk image that
does precisely this job. If this ever worked as advertised, it seems as if
the behaviour of vgscan/vgchange changed in a way not respected by
lvmcreate_initrd. In particular, either vgscan or vgchange tries to write
a considerable amount of temporary data into the ramdisk, more than it can
handle, which causes partition detection to fail.
Effect: it is not possible to disk-boot a system with / installed on LVM.
This presumably justifies the rating of this bug as "critical". (One may
argue that / never should be on LVM, however, (1) the official
documentation does not explicitly state so, (2) there are situations where
snapshotting for / is highly desirable.)
Solution:
The initrd created by lvmcreate_initrd should be a (compressed) ext2 image
of about 6 MB (uncompressed) size, created with increased inode density
(mke2fs -i 1024), containing everything from the image created by the
broken lvmcreate_initrd, as well as a directory etc/lvmtab.d - with such
an initrd, LVM detection and boot will work.
For completeness, here is a working GRUB menu.lst entry showing how to
boot such a system:
title Debian GNU/Linux LVM, kernel 2.4.31
root (hd0,0)
kernel /vmlinuz-2.4.31 root=3a05 ro vga=ext ramdisk_size=8192
initrd /initrd-lvm-2.4.30-repaired-manually.gz
savedefault
boot
Notes:
(*) It does not work to give part of the kernel args in the 'kernel' line,
and others (like ramdisk_size) in an extra 'append' line.
(*) Specifying the root= kernel parameter as [0-9a-f]{4} causes the kernel
to first look for a /dev/ entry with that name. If that fails, it tries to
boot from the device whose [major][minor] ID is the one given. LVM
usually has major ID 58, which is 3a in hex. The minor id designates the
partition and can be found out e.g. by looking into /proc/partitions of a
CD-booted system which has LVM activated.
--
regards, [EMAIL PROTECTED] (o_
Thomas Fischbacher - http://www.cip.physik.uni-muenchen.de/~tf //\
(lambda (n) ((lambda (p q r) (p p q r)) (lambda (g x y) V_/_
(if (= x 0) y (g g (- x 1) (* x y)))) n 1)) (Debian GNU)
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