bootup: "couldn't find a valid label"

[RJVB]

I modified one of my LinuxMintDebian-on-zfs set-ups yesterday. Its pool had an external mirror and because I didn't want the moral obligation to keep an external disk connected (it's a netbook), I decided to split its linux partition in 2and rebuild the pool using like so. The ext3 /boot partition was on sda7 where I left it:

$ zpool status -v
  pool: rpool
 state: ONLINE
  scan: resilvered 680K in 0h0m with 0 errors on Fri Jan 17 02:27:03 2014
config:

        NAME                                                  STATE     READ WRITE CKSUM
        rpool                                                 ONLINE       0     0     0
          mirror-0                                            ONLINE       0     0     0
            ata-WDC_WD3200BPVT-22JJ5T0_WD-WX81AA1M9437-part6  ONLINE       0     0     0
            ata-WDC_WD3200BPVT-22JJ5T0_WD-WX81AA1M9437-part8  ONLINE       0     0     0

errors: No known data errors

$ fdisk -l /dev/sda

Disk /dev/sda: 320.1 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x1e73b561

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1            2048    29362175    14680064   27  Hidden NTFS WinRE
/dev/sda2        29362176    29566975      102400    7  HPFS/NTFS/exFAT
/dev/sda3        29566976   327354367   148893696    7  HPFS/NTFS/exFAT
/dev/sda4       327354368   625141759   148893696    5  Extended
/dev/sda5       327356416   347836415    10240000   82  Linux swap / Solaris
/dev/sda6       347838464   485441535    68801536   83  Linux
/dev/sda7   *   623046656   625141759     1047552   83  Linux
/dev/sda8       485443584   623044607    68800512   83  Linux

Partition table entries are not in disk order

I know that this kind of mirroring isn't the most protective (but it ought to protect more against bit-rot than no mirror at all) and I notice now that gparted finally did not give me 2 perfectly identical partitions (6 & 8), but that's not the point here (or so I hope).

I've been doing quite a bit of linux-on-zfs setting up lately, so I was confident that the most time-consuming in this operation would be the 2 send/receive operations to and fro an external disk.

Instead, I've been spending hours rebuilding the initramfs, grub.cfg and rebooting, and I cannot seem to get rid of that boot error

"could not find a valid label"

After a pause, the boot continues, and until I renamed my pool from Patux to the default, rpool, I had to import and mount it by hand for the boot to complete.

Initially, I saw messages about sda6 and sda7 not being found in device.map (which I don't have), I think during update-grub. This was after 1:30 in the morning, so sadly I didn't think to save them. This morning, I almost thought the cycle looked good, but a reboot still showed that dreaded warning and I decided to raise this issue.

This time I kept a log:

$ update-initramfs -u -k all
update-initramfs: Generating /boot/initrd.img-3.10.5-amd64-rjvb
cryptsetup: WARNING: could not determine root device from /etc/fstab
update-initramfs: Generating /boot/initrd.img-3.10-2-amd64
cryptsetup: WARNING: could not determine root device from /etc/fstab
update-initramfs: Generating /boot/initrd.img-3.8.13-amd64-xen+rtai-rjvb
cryptsetup: WARNING: could not determine root device from /etc/fstab
update-initramfs: Generating /boot/initrd.img-3.2.0-4-amd64
cryptsetup: WARNING: could not determine root device from /etc/fstab
574.448 user_cpu 58.624 kernel_cpu 13:32.06 total_time 77.9%CPU {0W 0X 0D 0K 96360M 5204F 6561536R 832704I 119472O 0r 0s 0k 79044w 130926c}

$ update-grub
Generating grub.cfg ...
Found background image: .background_cache.png
Found linux image: /boot/vmlinuz-3.10.5-amd64-rjvb
Found initrd image: /boot/initrd.img-3.10.5-amd64-rjvb
Found linux image: /boot/vmlinuz-3.10-2-amd64
Found initrd image: /boot/initrd.img-3.10-2-amd64
Found linux image: /boot/vmlinuz-3.8.13-amd64-xen+rtai-rjvb
Found initrd image: /boot/initrd.img-3.8.13-amd64-xen+rtai-rjvb
Found linux image: /boot/vmlinuz-3.2.0-4-amd64
Found initrd image: /boot/initrd.img-3.2.0-4-amd64
Found Windows Recovery Environment (loader) on /dev/sda1
Found Windows 7 (loader) on /dev/sda2
done

$ grub-install --recheck /dev/sda
Installation finished. No error reported.

grub.cfg looks like 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 ###
if [ -s $prefix/grubenv ]; then
  set have_grubenv=true
  load_env
fi
set default="Windows 7 (loader) (on /dev/sda2)"

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$feature_default_font_path = xy ] ; then
   font=unicode
else
insmod part_msdos
insmod ext2
set root='hd0,msdos7'
if [ x$feature_platform_search_hint = xy ]; then
  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  39ff79e1-e153-490f-b302-4ba8e71fe643
else
  search --no-floppy --fs-uuid --set=root 39ff79e1-e153-490f-b302-4ba8e71fe643
fi
    font="/grub/unicode.pf2"
fi

if loadfont $font ; then
  set gfxmode=auto
  load_video
  insmod gfxterm
  set locale_dir=$prefix/locale
  set lang=en_GB
  insmod gettext
fi
terminal_output gfxterm
if [ "${recordfail}" = 1 ] ; then
  set timeout=-1
else
  set timeout=10
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###
insmod part_msdos
insmod ext2
set root='hd0,msdos7'
if [ x$feature_platform_search_hint = xy ]; then
  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  39ff79e1-e153-490f-b302-4ba8e71fe643
else
  search --no-floppy --fs-uuid --set=root 39ff79e1-e153-490f-b302-4ba8e71fe643
fi
insmod png
if background_image /grub/.background_cache.png; then
  set color_normal=white/black
  set color_highlight=black/white
else
  set menu_color_normal=cyan/blue
  set menu_color_highlight=white/blue
fi
### END /etc/grub.d/05_debian_theme ###

### BEGIN /etc/grub.d/06_mint_theme ###
set menu_color_normal=white/black
set menu_color_highlight=white/light-gray
### END /etc/grub.d/06_mint_theme ###

### BEGIN /etc/grub.d/10_linux ###
function gfxmode {
    set gfxpayload="${1}"
}
set linux_gfx_mode=
export linux_gfx_mode
menuentry 'LinuxMint GNU/Linux' --class linuxmint --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-/dev/sda6
/dev/sda8' {
    load_video
    insmod gzio
    insmod zfsinfo
    zfs-bootfs ($root) bootfs
    insmod part_msdos
    insmod ext2
    set root='hd0,msdos7'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  39ff79e1-e153-490f-b302-4ba8e71fe643
    else
      search --no-floppy --fs-uuid --set=root 39ff79e1-e153-490f-b302-4ba8e71fe643
    fi
    linux   /vmlinuz-3.10.5-amd64-rjvb root=ZFS=/ ro boot=zfs $bootfs   
    initrd  /initrd.img-3.10.5-amd64-rjvb
}
submenu 'Advanced options for LinuxMint GNU/Linux' $menuentry_id_option 'gnulinux-advanced-/dev/sda6
/dev/sda8' {
    menuentry 'LinuxMint GNU/Linux, with Linux 3.10.5-amd64-rjvb' --class linuxmint --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.10.5-amd64-rjvb-advanced-/dev/sda6
    /dev/sda8' {
        load_video
        insmod gzio
        insmod zfsinfo
        zfs-bootfs ($root) bootfs
        insmod part_msdos
        insmod ext2
        set root='hd0,msdos7'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  39ff79e1-e153-490f-b302-4ba8e71fe643
        else
          search --no-floppy --fs-uuid --set=root 39ff79e1-e153-490f-b302-4ba8e71fe643
        fi
        echo    'Loading Linux 3.10.5-amd64-rjvb ...'
        linux   /vmlinuz-3.10.5-amd64-rjvb root=ZFS=/ ro boot=zfs $bootfs   
        echo    'Loading initial ramdisk ...'
        initrd  /initrd.img-3.10.5-amd64-rjvb
    }
    menuentry 'LinuxMint GNU/Linux, with Linux 3.10.5-amd64-rjvb (recovery mode)' --class linuxmint --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.10.5-amd64-rjvb-recovery-/dev/sda6
    /dev/sda8' {
        load_video
        insmod gzio
        insmod zfsinfo
        zfs-bootfs ($root) bootfs
        insmod part_msdos
        insmod ext2
        set root='hd0,msdos7'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  39ff79e1-e153-490f-b302-4ba8e71fe643
        else
          search --no-floppy --fs-uuid --set=root 39ff79e1-e153-490f-b302-4ba8e71fe643
        fi
        echo    'Loading Linux 3.10.5-amd64-rjvb ...'
        linux   /vmlinuz-3.10.5-amd64-rjvb root=ZFS=/ ro single boot=zfs $bootfs 
        echo    'Loading initial ramdisk ...'
        initrd  /initrd.img-3.10.5-amd64-rjvb
    }
    menuentry 'LinuxMint GNU/Linux, with Linux 3.10-2-amd64' --class linuxmint --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.10-2-amd64-advanced-/dev/sda6
    /dev/sda8' {
        load_video
        insmod gzio
        insmod zfsinfo
        zfs-bootfs ($root) bootfs
        insmod part_msdos
        insmod ext2
        set root='hd0,msdos7'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  39ff79e1-e153-490f-b302-4ba8e71fe643
        else
          search --no-floppy --fs-uuid --set=root 39ff79e1-e153-490f-b302-4ba8e71fe643
        fi
        echo    'Loading Linux 3.10-2-amd64 ...'
        linux   /vmlinuz-3.10-2-amd64 root=ZFS=/ ro boot=zfs $bootfs   
        echo    'Loading initial ramdisk ...'
        initrd  /initrd.img-3.10-2-amd64
    }
    menuentry 'LinuxMint GNU/Linux, with Linux 3.10-2-amd64 (recovery mode)' --class linuxmint --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.10-2-amd64-recovery-/dev/sda6
    /dev/sda8' {
        load_video
        insmod gzio
        insmod zfsinfo
        zfs-bootfs ($root) bootfs
        insmod part_msdos
        insmod ext2
        set root='hd0,msdos7'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  39ff79e1-e153-490f-b302-4ba8e71fe643
        else
          search --no-floppy --fs-uuid --set=root 39ff79e1-e153-490f-b302-4ba8e71fe643
        fi
        echo    'Loading Linux 3.10-2-amd64 ...'
        linux   /vmlinuz-3.10-2-amd64 root=ZFS=/ ro single boot=zfs $bootfs 
        echo    'Loading initial ramdisk ...'
        initrd  /initrd.img-3.10-2-amd64
    }
    menuentry 'LinuxMint GNU/Linux, with Linux 3.8.13-amd64-xen+rtai-rjvb' --class linuxmint --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.8.13-amd64-xen+rtai-rjvb-advanced-/dev/sda6
    /dev/sda8' {
        load_video
        insmod gzio
        insmod zfsinfo
        zfs-bootfs ($root) bootfs
        insmod part_msdos
        insmod ext2
        set root='hd0,msdos7'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  39ff79e1-e153-490f-b302-4ba8e71fe643
        else
          search --no-floppy --fs-uuid --set=root 39ff79e1-e153-490f-b302-4ba8e71fe643
        fi
        echo    'Loading Linux 3.8.13-amd64-xen+rtai-rjvb ...'
        linux   /vmlinuz-3.8.13-amd64-xen+rtai-rjvb root=ZFS=/ ro boot=zfs $bootfs   
        echo    'Loading initial ramdisk ...'
        initrd  /initrd.img-3.8.13-amd64-xen+rtai-rjvb
    }
    menuentry 'LinuxMint GNU/Linux, with Linux 3.8.13-amd64-xen+rtai-rjvb (recovery mode)' --class linuxmint --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.8.13-amd64-xen+rtai-rjvb-recovery-/dev/sda6
    /dev/sda8' {
        load_video
        insmod gzio
        insmod zfsinfo
        zfs-bootfs ($root) bootfs
        insmod part_msdos
        insmod ext2
        set root='hd0,msdos7'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  39ff79e1-e153-490f-b302-4ba8e71fe643
        else
          search --no-floppy --fs-uuid --set=root 39ff79e1-e153-490f-b302-4ba8e71fe643
        fi
        echo    'Loading Linux 3.8.13-amd64-xen+rtai-rjvb ...'
        linux   /vmlinuz-3.8.13-amd64-xen+rtai-rjvb root=ZFS=/ ro single boot=zfs $bootfs 
        echo    'Loading initial ramdisk ...'
        initrd  /initrd.img-3.8.13-amd64-xen+rtai-rjvb
    }
    menuentry 'LinuxMint GNU/Linux, with Linux 3.2.0-4-amd64' --class linuxmint --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.2.0-4-amd64-advanced-/dev/sda6
    /dev/sda8' {
        load_video
        insmod gzio
        insmod zfsinfo
        zfs-bootfs ($root) bootfs
        insmod part_msdos
        insmod ext2
        set root='hd0,msdos7'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  39ff79e1-e153-490f-b302-4ba8e71fe643
        else
          search --no-floppy --fs-uuid --set=root 39ff79e1-e153-490f-b302-4ba8e71fe643
        fi
        echo    'Loading Linux 3.2.0-4-amd64 ...'
        linux   /vmlinuz-3.2.0-4-amd64 root=ZFS=/ ro boot=zfs $bootfs   
        echo    'Loading initial ramdisk ...'
        initrd  /initrd.img-3.2.0-4-amd64
    }
    menuentry 'LinuxMint GNU/Linux, with Linux 3.2.0-4-amd64 (recovery mode)' --class linuxmint --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.2.0-4-amd64-recovery-/dev/sda6
    /dev/sda8' {
        load_video
        insmod gzio
        insmod zfsinfo
        zfs-bootfs ($root) bootfs
        insmod part_msdos
        insmod ext2
        set root='hd0,msdos7'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  39ff79e1-e153-490f-b302-4ba8e71fe643
        else
          search --no-floppy --fs-uuid --set=root 39ff79e1-e153-490f-b302-4ba8e71fe643
        fi
        echo    'Loading Linux 3.2.0-4-amd64 ...'
        linux   /vmlinuz-3.2.0-4-amd64 root=ZFS=/ ro single boot=zfs $bootfs 
        echo    'Loading initial ramdisk ...'
        initrd  /initrd.img-3.2.0-4-amd64
    }
}

### 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 Recovery Environment (loader) (on /dev/sda1)' --class windows --class os $menuentry_id_option 'osprober-chain-68C25524C254F7B0' {
    insmod part_msdos
    insmod ntfs
    set root='hd0,msdos1'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1  68C25524C254F7B0
    else
      search --no-floppy --fs-uuid --set=root 68C25524C254F7B0
    fi
    drivemap -s (hd0) ${root}
    chainloader +1
}
menuentry 'Windows 7 (loader) (on /dev/sda2)' --class windows --class os $menuentry_id_option 'osprober-chain-EA8655BD86558B49' {
    insmod part_msdos
    insmod ntfs
    set root='hd0,msdos2'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos2 --hint-efi=hd0,msdos2 --hint-baremetal=ahci0,msdos2  EA8655BD86558B49
    else
      search --no-floppy --fs-uuid --set=root EA8655BD86558B49
    fi
    chainloader +1
}
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/30_uefi-firmware ###
### END /etc/grub.d/30_uefi-firmware ###

### 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 ###

So what is that label that's not being found as the first thing during the boot process after I selected the desired grub entry? Why is it that I could boot with my pool name of choice (and still can on my other set-up, rebuilt no later than last Monday, with a copy of this netbook's pool?)
Could it be the fact that there's a newline in the -class os $menuentry_id_option?

Is there anything else I'd have to upload to diagnose this issue?

[RJVB]

Addendum: there does seem to be an issue with grub, in how it handles mirrored pools.

I split rpool, which gave me a pool on only ata-WDC_WD3200BPVT-22JJ5T0_WD-WX81AA1M9437-part6, ran update-grub; grub-install and reboot.
Result, the system rebooted fine.

The pool is now resilvering after I added back ata-WDC_WD3200BPVT-22JJ5T0_WD-WX81AA1M9437-part8 to it, I will report back if rebooting with it gives a new issue. I have no reason to expect it will ...

...

as long as I don't (have to) rebuild grub.cfg !

[RJVB]

Compar:

if [ x$feature_default_font_path = xy ] ; then
   font=unicode
else
insmod part_msdos
insmod ext2
set root='hd0,msdos7'
if [ x$feature_platform_search_hint = xy ]; then
  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  39ff79e1-e153-490f-b302-4ba8e71fe643
else
  search --no-floppy --fs-uuid --set=root 39ff79e1-e153-490f-b302-4ba8e71fe643
fi
    font="/grub/unicode.pf2"
fi

if loadfont $font ; then
  set gfxmode=auto
  load_video
  insmod gfxterm
  set locale_dir=$prefix/locale
  set lang=en_GB
  insmod gettext
fi
terminal_output gfxterm
if [ "${recordfail}" = 1 ] ; then
  set timeout=-1
else
  set timeout=10
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###
insmod part_msdos
insmod ext2
set root='hd0,msdos7'
if [ x$feature_platform_search_hint = xy ]; then
  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  39ff79e1-e153-490f-b302-4ba8e71fe643
else
  search --no-floppy --fs-uuid --set=root 39ff79e1-e153-490f-b302-4ba8e71fe643
fi
insmod png
if background_image /grub/.background_cache.png; then
  set color_normal=white/black
  set color_highlight=black/white
else
  set menu_color_normal=cyan/blue
  set menu_color_highlight=white/blue
fi
### END /etc/grub.d/05_debian_theme ###

with

if [ x$feature_default_font_path = xy ] ; then
   font=unicode
else
insmod part_msdos
insmod zfs
set root='hd0,msdos6'
if [ x$feature_platform_search_hint = xy ]; then
  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos6 --hint-efi=hd0,msdos6 --hint-baremetal=ahci0,msdos6  f97c41755c6bece7
else
  search --no-floppy --fs-uuid --set=root f97c41755c6bece7
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_GB
  insmod gettext
fi
terminal_output gfxterm
if [ "${recordfail}" = 1 ] ; then
  set timeout=-1
else
  set timeout=10
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###
insmod part_msdos
insmod zfs
set root='hd0,msdos6'
if [ x$feature_platform_search_hint = xy ]; then
  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos6 --hint-efi=hd0,msdos6 --hint-baremetal=ahci0,msdos6  f97c41755c6bece7
else
  search --no-floppy --fs-uuid --set=root f97c41755c6bece7
fi
insmod png
if background_image /@/usr/share/images/desktop-base/joy-grub.png; then
  set color_normal=white/black
  set color_highlight=black/white
else
  set menu_color_normal=cyan/blue
  set menu_color_highlight=white/blue
fi
### END /etc/grub.d/05_debian_theme ###

The former is an extract from grub.cfg generated when update-grub is run with a mirrored pool, the latter with a pool without redundancy. Note how the former grub.cfg sets the root to the /boot partition, while the latter sets it to the zfs partition, referenced through its guid (took me a while to figure out that one :) )

[FransUrbo]

@RJVB This is not an issue with ZoL. Please move this to https://github.com/zfsonlinux/grub.

[behlendorf]

Closing, it was migrated to zfsonlinux/grub#13.