[SOLVED] Grub boots to rescue mode err: unknown filesystem every drive

Question

So I installed Arch and it all seemed to go reasonably well (well, had a little trouble installing GRUB to begin with, but I think that's just because I needed a BIOS boot partition at the start of the drive). I installed it onto a 4TB I have, which due to its size has a GPT partition table even though my mobo (Gigabyte GA-P67A-UD4-B3, don't think it matters though) uses a regular old BIOS. Initially it was two partitions, the Microsoft reserved partition then a big NTFS data partition. I shrunk the NTFS partition and then made (in this order on the disk, starting at third) an ext4 partition for /boot, a swap partition, and a big btrfs partition (in which I created subvolumes for /, /etc, /home and /var). GRUB wouldn't install (I forgot the exact error) but what I could find suggested it was because there needed to be room for it at the start of the disk, so I deleted the Microsoft reserved partition (Windows is installed on an SSD, and its bootloader is on another hard drive entirely, so I didn't think I needed it) and created an empty partition with the right code using gdisk, then I could install GRUB to the 4TB HDD.
Unfortunately, when I try to boot into GRUB it immediately comes up with error: unknown filesystem and dumps me at the GRUB rescue prompt. Using ls, I can see my HDDs and their partitions, but whenever I try to use (for example) ls (hd0,gpt3)/ - which I think should probably be the ext4 boot partition, but it does this for everything - it just says error: unknown filesystem again.
This seems pretty close to (if not exactly the same as) my problem, so I tried what he suggested, but when I tried to run the command he says worked, (grub-install --recheck --disk-module=native /dev/sda) - and don't worry, I didn't do that blindly, I know /dev/sda is my 4TB HDD - I just get the error grub-install: --disk-module: (PROGRAM ERROR) Option should have been recognized!?. So I'm all out of ideas and I've been trying for a few hours. Please help me, before I go insane... more insane. I can boot the USB drive I used to install Arch and chroot into my installation, but I haven't found a way to actually boot the installation yet.
SOLVED: Apparently the partition I was using for /boot was too far back on the drive (past the first 2TB). When I shuffled partitions around so that the /boot partition was near the start of the drive (it starts at sector 2048 now!) that seemed to fix it.
Last edited by Slashee the Cow (2015-04-12 15:36:51)

Answer 1

Tried using insmod btrfs in the grub rescue shell last night. Didn't work, can't remember if the insmod command itself gave me an error or whether it still couldn't see any files or anything. Tried it again today, but that was after I converted /dev/sda3 back to ext4 and mounted it at /boot (since it being ext2 wasn't working, and not using it wasn't working, so I figure what's the harm) and I just got error: unknown filesystem.
Anyway: using grub-install from outside chroot seems to work (still can't use --disk-module), but grub-mkconfig just generates this:
# 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 ext2
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root ec4cf3cd-d72d-4988-a2ce-421f45d52824
else
search --no-floppy --fs-uuid --set=root ec4cf3cd-d72d-4988-a2ce-421f45d52824
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
if [ x$feature_timeout_style = xy ] ; then
set timeout_style=menu
set timeout=5
# Fallback normal timeout code in case the timeout_style feature is
# unavailable.
else
set timeout=5
fi
### END /etc/grub.d/00_header ###
### BEGIN /etc/grub.d/10_linux ###
### 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 $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###
### BEGIN /etc/grub.d/60_memtest86+ ###
if [ "${grub_platform}" == "pc" ]; then
menuentry "Memory Tester (memtest86+)" --class memtest86 --class gnu --class tool {
search --fs-uuid --no-floppy --set=root ec4cf3cd-d72d-4988-a2ce-421f45d52824
linux16 /boot/memtest86+/memtest.bin
fi
### END /etc/grub.d/60_memtest86+ ###
I'm not an expert on GRUB configuration files, but I figured that even if that didn't just boot me straight to the rescue shell, it wasn't going to boot anything... other than memtest86+ maybe. So I went back into chroot and run grub-mkconfig and it generated this:
# 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_gpt
insmod btrfs
set root='hd0,gpt5'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt5 --hint-efi=hd0,gpt5 --hint-baremetal=ahci0,gpt5 b21e6211-5e7a-4769-9f53-b9b5d554a242
else
search --no-floppy --fs-uuid --set=root b21e6211-5e7a-4769-9f53-b9b5d554a242
fi
font="/root/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
if [ x$feature_timeout_style = xy ] ; then
set timeout_style=menu
set timeout=5
# Fallback normal timeout code in case the timeout_style feature is
# unavailable.
else
set timeout=5
fi
### END /etc/grub.d/00_header ###
### BEGIN /etc/grub.d/10_linux ###
menuentry 'Arch Linux' --class arch --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-b21e6211-5e7a-4769-9f53-b9b5d554a242' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_gpt
insmod ext2
set root='hd0,gpt3'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt3 --hint-efi=hd0,gpt3 --hint-baremetal=ahci0,gpt3 184916fd-57a7-48cf-858e-93a5d339ade2
else
search --no-floppy --fs-uuid --set=root 184916fd-57a7-48cf-858e-93a5d339ade2
fi
echo 'Loading Linux linux ...'
linux /vmlinuz-linux root=UUID=b21e6211-5e7a-4769-9f53-b9b5d554a242 rw rootflags=subvol=root quiet
echo 'Loading initial ramdisk ...'
initrd /initramfs-linux.img
submenu 'Advanced options for Arch Linux' $menuentry_id_option 'gnulinux-advanced-b21e6211-5e7a-4769-9f53-b9b5d554a242' {
menuentry 'Arch Linux, with Linux linux' --class arch --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-linux-advanced-b21e6211-5e7a-4769-9f53-b9b5d554a242' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_gpt
insmod ext2
set root='hd0,gpt3'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt3 --hint-efi=hd0,gpt3 --hint-baremetal=ahci0,gpt3 184916fd-57a7-48cf-858e-93a5d339ade2
else
search --no-floppy --fs-uuid --set=root 184916fd-57a7-48cf-858e-93a5d339ade2
fi
echo 'Loading Linux linux ...'
linux /vmlinuz-linux root=UUID=b21e6211-5e7a-4769-9f53-b9b5d554a242 rw rootflags=subvol=root quiet
echo 'Loading initial ramdisk ...'
initrd /initramfs-linux.img
menuentry 'Arch Linux, with Linux linux (fallback initramfs)' --class arch --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-linux-fallback-b21e6211-5e7a-4769-9f53-b9b5d554a242' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_gpt
insmod ext2
set root='hd0,gpt3'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt3 --hint-efi=hd0,gpt3 --hint-baremetal=ahci0,gpt3 184916fd-57a7-48cf-858e-93a5d339ade2
else
search --no-floppy --fs-uuid --set=root 184916fd-57a7-48cf-858e-93a5d339ade2
fi
echo 'Loading Linux linux ...'
linux /vmlinuz-linux root=UUID=b21e6211-5e7a-4769-9f53-b9b5d554a242 rw rootflags=subvol=root 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 ###
menuentry 'Windows Vista (loader) (on /dev/sdb1)' --class windows --class os $menuentry_id_option 'osprober-chain-4E94BAB294BA9C41' {
insmod part_gpt
insmod ntfs
set root='hd1,gpt1'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd1,gpt1 --hint-efi=hd1,gpt1 --hint-baremetal=ahci1,gpt1 4E94BAB294BA9C41
else
search --no-floppy --fs-uuid --set=root 4E94BAB294BA9C41
fi
chainloader +1
menuentry 'Windows Vista (loader) (on /dev/sde1)' --class windows --class os $menuentry_id_option 'osprober-chain-CEF01053F010445D' {
insmod part_msdos
insmod ntfs
set root='hd4,msdos1'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd4,msdos1 --hint-efi=hd4,msdos1 --hint-baremetal=ahci4,msdos1 CEF01053F010445D
else
search --no-floppy --fs-uuid --set=root CEF01053F010445D
fi
chainloader +1
menuentry 'Windows Vista (loader) (on /dev/sde5)' --class windows --class os $menuentry_id_option 'osprober-chain-4E94BAB294BA9C41' {
insmod part_msdos
insmod ntfs
set root='hd4,msdos5'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd4,msdos5 --hint-efi=hd4,msdos5 --hint-baremetal=ahci4,msdos5 4E94BAB294BA9C41
else
search --no-floppy --fs-uuid --set=root 4E94BAB294BA9C41
fi
chainloader +1
### 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+ ###
Still didn't work though.
I don't know grub config, but is the UUID specified in
linux /vmlinuz-linux root=UUID=b21e6211-5e7a-4769-9f53-b9b5d554a242 rw rootflags=subvol=root quiet
supposed to be the UUID for /boot or /? Because the UUID there is for the btrfs partition being mounted at / (which I guess would explain why it has the correct subvol listed, which I'm not sure if it's necessary, given that should be the default subvolume). So... that's probably alright (just something that stood out to me).
As for installing grub on another disk: I suppose I could try, though I'd rather keep it on one drive if I can (sometimes it gets complicated enough having Windows and my Windows bootloader on different drives... I should probably try moving the Windows bootloader to the SSD where Windows is installed. Would it matter which drive? The options are:
sda: 4TB, GPT table, the one I'm having problems with now
sdb: 2TB, MBR table, nothing in boot sector AFAIK
sdc: 240GB SSD, GPT table, would rather not use it since Windows is installed on there, even if its bootloader isn't
sdd: 1TB, MBR table, nothing in boot sector AFAIK
sde: 500GB, MBR table, has the Windows bootloader so I'd rather not mess that up (although given it's the smallest and I have no free SATA ports, it'll be next to go when I need more space, so I might want to move the bootloader)
(sdf and sdg which appear in lsblk earlier are just USB flash drives, and I'd rather not have to rely on having to use one of them to boot Linux).
As for repartitioning /dev/sda: as long as I can do it non-destructively, sure. Well I mean non-destructively for the NTFS partition, which is mostly full of Steam games (and I might have enough room on other drives and portable drives to keep the rest safe), but on my crappy Australian internet connection (aren't they all) it'd probably take me a couple of weeks to redownload them. I don't mind if I have to get rid of the Linux partitions, I already tried going through the install again once before to try to get it to work, another time isn't going to matter. So I guess I could try using gparted to delete the Linux partitions, move the NTFS partition to the end of the disk, and recreate the Linux partitions in front of it (although moving that much data might take a while, so I'd probably want to do it overnight). For reference, right now it's:
128MB of unformatted space (where the Microsoft reserved partition was, but now it's flagged as a BIOS boot partition, even though it's far bigger than it needs to be for that, I didn't feel like moving the other partitions back just to claim less than 128MB)
~2.7TB NTFS data partition (important)
~1GB ext4 /boot partition
8GB swap partition
~1TB btrfs partition with subvolumes mounted at /, /home, /etc and /var