[Solved] Installing and using GRUB on LVM

Question

New installation, no more windows, using LVM.
pvdisplay :
--- Physical volume ---
PV Name /dev/sda1
VG Name DesktopLVM
PV Size 243.14 MiB / not usable 3.14 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 60
Free PE 0
Allocated PE 60
PV UUID 9LXTZW-zZNI-dQ3W-RMTD-C3Fl-5blw-TbPwOo
--- Physical volume ---
PV Name /dev/sda2
VG Name DesktopLVM
PV Size 19.07 GiB / not usable 4.15 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 4882
Free PE 0
Allocated PE 4882
PV UUID bgu0dD-seVt-nz7i-3Vdi-PZ4U-MKKa-pk3i6V
--- Physical volume ---
PV Name /dev/sda3
VG Name DesktopLVM
PV Size 7.63 GiB / not usable 4.86 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 1952
Free PE 0
Allocated PE 1952
PV UUID lybKyF-aqIM-3tTA-FEH3-LRPn-cjI5-qqhG75
--- Physical volume ---
PV Name /dev/sda4
VG Name DesktopLVM
PV Size 438.82 GiB / not usable 3.84 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 112337
Free PE 0
Allocated PE 112337
PV UUID l1h3Hh-BkzT-Fj0q-9mDH-1IGx-DtI0-v8AGgS
lvdisplay :
--- Logical volume ---
LV Path /dev/DesktopLVM/boot
LV Name boot
VG Name DesktopLVM
LV UUID Je7Lat-TOzj-vWei-5fLe-4cc8-ZAUF-J2IGAu
LV Write Access read/write
LV Creation host, time archiso, 2013-08-01 16:54:03 +0000
LV Status available
# open 1
LV Size 256.00 MiB
Current LE 64
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:1
--- Logical volume ---
LV Path /dev/DesktopLVM/root
LV Name root
VG Name DesktopLVM
LV UUID xRK2SN-4IG1-RjNV-RHAl-qeXL-R8F3-k4SDQt
LV Write Access read/write
LV Creation host, time archiso, 2013-08-01 16:54:12 +0000
LV Status available
# open 1
LV Size 20.00 GiB
Current LE 5120
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:2
--- Logical volume ---
LV Path /dev/DesktopLVM/var
LV Name var
VG Name DesktopLVM
LV UUID Ej5zmm-7Q2x-HubD-JCBp-rg3F-g1oo-4rGBEn
LV Write Access read/write
LV Creation host, time archiso, 2013-08-01 16:54:21 +0000
LV Status available
# open 1
LV Size 8.00 GiB
Current LE 2048
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:3
--- Logical volume ---
LV Path /dev/DesktopLVM/home
LV Name home
VG Name DesktopLVM
LV UUID jU5Fdz-Tgdl-wPeE-ePOB-NaZk-CsGN-Xc8rkn
LV Write Access read/write
LV Creation host, time archiso, 2013-08-01 16:54:37 +0000
LV Status available
# open 1
LV Size 437.50 GiB
Current LE 111999
Segments 4
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:4
The problem is when using grub-install :
sh-4.2# grub-install --recheck /dev/sda
WARNING: Failed to connect to lvmetad: No such file or directory. Falling back to internal scanning.
WARNING: Failed to connect to lvmetad: No such file or directory. Falling back to internal scanning.
WARNING: Failed to connect to lvmetad: No such file or directory. Falling back to internal scanning.
WARNING: Failed to connect to lvmetad: No such file or directory. Falling back to internal scanning.
WARNING: Failed to connect to lvmetad: No such file or directory. Falling back to internal scanning.
WARNING: Failed to connect to lvmetad: No such file or directory. Falling back to internal scanning.
WARNING: Failed to connect to lvmetad: No such file or directory. Falling back to internal scanning.
WARNING: Failed to connect to lvmetad: No such file or directory. Falling back to internal scanning.
WARNING: Failed to connect to lvmetad: No such file or directory. Falling back to internal scanning.
/usr/bin/grub-bios-setup: warning: your core.img is unusually large. It won't fit in the embedding area.
/usr/bin/grub-bios-setup: error: embedding is not possible, but this is required for RAID and LVM install.
cat /boot/grub/grub.cfg :
# DO NOT EDIT THIS FILE
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
### BEGIN /etc/grub.d/00_header ###
insmod part_gpt
insmod part_msdos
if [ -s $prefix/grubenv ]; then
load_env
fi
if [ "${next_entry}" ] ; then
set default="${next_entry}"
set next_entry=
save_env next_entry
set boot_once=true
else
set default="0"
fi
if [ x"${feature_menuentry_id}" = xy ]; then
menuentry_id_option="--id"
else
menuentry_id_option=""
fi
export menuentry_id_option
if [ "${prev_saved_entry}" ]; then
set saved_entry="${prev_saved_entry}"
save_env saved_entry
set prev_saved_entry=
save_env prev_saved_entry
set boot_once=true
fi
function savedefault {
if [ -z "${boot_once}" ]; then
saved_entry="${chosen}"
save_env saved_entry
fi
function load_video {
if [ x$feature_all_video_module = xy ]; then
insmod all_video
else
insmod efi_gop
insmod efi_uga
insmod ieee1275_fb
insmod vbe
insmod vga
insmod video_bochs
insmod video_cirrus
fi
if [ x$feature_default_font_path = xy ] ; then
font=unicode
else
insmod part_msdos
insmod part_msdos
insmod part_msdos
insmod part_msdos
insmod lvm
insmod ext2
set root='lvm/DesktopLVM-root'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint='lvm/DesktopLVM-root' b881e4e6-ad72-495c-8ae1-610ec15d27c8
else
search --no-floppy --fs-uuid --set=root b881e4e6-ad72-495c-8ae1-610ec15d27c8
fi
font="/usr/share/grub/unicode.pf2"
fi
if loadfont $font ; then
set gfxmode=auto
load_video
insmod gfxterm
set locale_dir=$prefix/locale
set lang=en_US
insmod gettext
fi
terminal_input console
terminal_output gfxterm
set timeout=5
### END /etc/grub.d/00_header ###
### BEGIN /etc/grub.d/10_linux ###
menuentry 'Arch Linux, with Linux core repo kernel' --class arch --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-core repo kernel-true-b881e4e6-ad72-495c-8ae1-610ec15d27c8' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_msdos
insmod part_msdos
insmod part_msdos
insmod part_msdos
insmod lvm
insmod ext2
set root='lvm/DesktopLVM-boot'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint='lvm/DesktopLVM-boot' edf3011c-e581-448e-baad-d1e03d5fb8f6
else
search --no-floppy --fs-uuid --set=root edf3011c-e581-448e-baad-d1e03d5fb8f6
fi
echo 'Loading Linux core repo kernel ...'
linux /vmlinuz-linux root=/dev/mapper/DesktopLVM-root ro quiet
echo 'Loading initial ramdisk ...'
initrd /initramfs-linux.img
menuentry 'Arch Linux, with Linux core repo kernel (Fallback initramfs)' --class arch --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-core repo kernel-fallback-b881e4e6-ad72-495c-8ae1-610ec15d27c8' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_msdos
insmod part_msdos
insmod part_msdos
insmod part_msdos
insmod lvm
insmod ext2
set root='lvm/DesktopLVM-boot'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint='lvm/DesktopLVM-boot' edf3011c-e581-448e-baad-d1e03d5fb8f6
else
search --no-floppy --fs-uuid --set=root edf3011c-e581-448e-baad-d1e03d5fb8f6
fi
echo 'Loading Linux core repo kernel ...'
linux /vmlinuz-linux root=/dev/mapper/DesktopLVM-root ro quiet
echo 'Loading initial ramdisk ...'
initrd /initramfs-linux-fallback.img
### END /etc/grub.d/10_linux ###
### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###
### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###
### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries. Simply type the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###
### BEGIN /etc/grub.d/41_custom ###
if [ -f ${config_directory}/custom.cfg ]; then
source ${config_directory}/custom.cfg
elif [ -z "${config_directory}" -a -f $prefix/custom.cfg ]; then
source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###
### BEGIN /etc/grub.d/60_memtest86+ ###
### END /etc/grub.d/60_memtest86+ ###
Partially related, fdisk -l :
Disk /dev/sda: 500.1 GB, 500107862016 bytes, 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x1bbed4e9
Device Boot Start End Blocks Id System
/dev/sda1 * 63 498014 248976 8e Linux LVM
/dev/sda2 498015 40499864 20000925 8e Linux LVM
/dev/sda3 40499865 56500604 8000370 8e Linux LVM
/dev/sda4 56500605 976773167 460136281+ 8e Linux LVM
Disk /dev/mapper/arch_root-image: 1494 MB, 1494220800 bytes, 2918400 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/DesktopLVM-boot: 268 MB, 268435456 bytes, 524288 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/DesktopLVM-root: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/DesktopLVM-var: 8589 MB, 8589934592 bytes, 16777216 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/DesktopLVM-home: 469.8 GB, 469757853696 bytes, 917495808 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
How do i install grub now ?
L.E. : do not include the boot partition into LVM.
Last edited by psycho (2013-08-01 18:58:18)

Answer 1

Your first partition starts at block 63.  Grub has gotten so bloated that it now writes to not only the MBR, but also to the space from the MBR (after sector 0) to the start of the first partition, which these days is sector 2048.  This new start point is for alignment purposes.
You either need to recreate your first partition and let fdsik align it to sector 2048, or you need to create a grub bios boot partition (as though you were using GPT).
Honestly, although grub2 can handle this, I think putting /boot inside the LVM is a bad idea.  It just makes you totally reliant on grub2 with no other bootloader choice.  For example, if something in some poorly designed program decided to write some crap to the area between the MBR and the first partition (which applications have been known to do), and you had a USB flash drive with syslinux on it (which the Arch live media has), then you could not set it up to boot your disc.
I think you should use the pvremove command to take that first partition out temporarily, then create two new partitions.  One for /boot and one to add back.  But this is not going to be very straight forward since you already have four primary partitions.  It might be better to convert your partitions to GPT (which is super easy using gdisk) because then you are limited to only 128 primary partitions instead of a measly four.  If you do that though, then you will have to make three new partitions if you want to continue to use grub2.  You will additionally need the grub bios partition mentioned above.  The grub2 wiki page had more info on this.  But then you should make the /boot partition and then the partition to add back.
At the very least, you are going to have to remove the first partition so that it can be resized, and then add it back.  Hopefully, you have not already filled the LVM space, so that you can easily shift things around.