$ sudo update-grub
/usr/sbin/grub-probe: error: failed to get canonical path of `none'.
This is the situation I'm in after an interrupted upgrade from vivid to wily
[edit]
Further delving into grub source code, the second command is probably the failing one:
$ grub-probe --target=device /
/dev/md2
$ grub-probe --target=device /boot
grub-probe: error: failed to get canonical path of `none'.
The following also gives the error:
$ sudo grub-probe -t device /boot/grub
grub-probe: error: failed to get canonical path of `none'.
$ sudo grub-probe -t fs_uuid /boot/grub
grub-probe: error: failed to get canonical path of `none'.
[/edit]
I don't have /boot/grub/grub.cfg present (or older /boot/grub/menu.lst)
It was impossible to install a boot loader during grub configuration:
Grub failed to install on the available options (/dev/sda /dev/sdb or /dev/md2)
md1 wasn't given as an option, even though it is currently mounted at /boot :
$ cat /etc/fstab
proc /proc proc defaults 0 0
/dev/md/0 none swap sw 0 0
/dev/md/1 /boot ext3 defaults 0 0
/dev/md/2 / ext4 defaults 0 0
I've got a raid setup with /dev/sda and /dev/sdb anyhow:
$ sudo fdisk -l
Disk /dev/sda: 447.1 GiB, 480103981056 bytes, 937703088 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
Disklabel type: dos
Disk identifier: 0x00032e61
Device Boot Start End Sectors Size Id Type
/dev/sda1 2048 8390656 8388609 4G fd Linux raid autodetect
/dev/sda2 8392704 9441280 1048577 512M fd Linux raid autodetect
/dev/sda3 9443328 937701040 928257713 442.6G fd Linux raid autodetect
Disk /dev/sdb: 447.1 GiB, 480103981056 bytes, 937703088 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
Disklabel type: dos
Disk identifier: 0x00074c3d
Device Boot Start End Sectors Size Id Type
/dev/sdb1 2048 8390656 8388609 4G fd Linux raid autodetect
/dev/sdb2 8392704 9441280 1048577 512M fd Linux raid autodetect
/dev/sdb3 9443328 937701040 928257713 442.6G fd Linux raid autodetect
Disk /dev/md2: 442.5 GiB, 475133575168 bytes, 927995264 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/md0: 4 GiB, 4292804608 bytes, 8384384 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/md1: 511.7 MiB, 536543232 bytes, 1047936 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
Grub appears to be installed (detection from another answer on serverfault):
$ sudo dd bs=512 count=1 if=/dev/sda 2>/dev/null | strings
ZRr=
`|f
\|f1
GRUB
Geom
Hard Disk
Read
Error
When I run grub-emu, I get a blank prompt:
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 15.10
Release: 15.10
Codename: wily
This is on a server with only ssh access so I don't have access to the live CD if grub fails!
[edit] output of df -h:
$ df -h
Filesystem Size Used Avail Use% Mounted on
udev 63G 0 63G 0% /dev
tmpfs 13G 714M 12G 6% /run
/dev/md2 436G 178G 236G 44% /
tmpfs 63G 8.0K 63G 1% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 63G 0 63G 0% /sys/fs/cgroup
none 436G 178G 236G 44% /boot
tmpfs 13G 0 13G 0% /run/user/0
tmpfs 13G 0 13G 0% /run/user/1002
/dev/md2 436G 178G 236G 44% /var/cache/apt/archives
none 436G 178G 236G 44% /bin
none 436G 178G 236G 44% /etc
none 436G 178G 236G 44% /initrd
none 436G 178G 236G 44% /lib
none 436G 178G 236G 44% /lib32
none 436G 178G 236G 44% /lib64
none 436G 178G 236G 44% /sbin
none 436G 178G 236G 44% /usr
none 436G 178G 236G 44% /var
[further edit] the above command seems to report that /boot is mounted at none. I think this might be the none grub-probe is complaining about. Here's the output of mount -l which shows two separate mount 'entries'; investigating how to remove the second now.
mount -l |grep boot
/dev/md1 on /boot type ext3 (rw,relatime,data=ordered)
none on /boot type aufs (rw,relatime,si=6ea5aad590be877d)
Ok I seem to have got it with the following (everything is simple in retrospect):
I tried this as I noticed that there were two 'mounts' for /boot:
And that the latter was overriding the former:
After umount the same commands look like this:
(no idea how the second mount happened)
I was then able to reinstall grub as follows (I've raid1 so that's why there's two commands for sda and sdb):
Postscript
After reboot the server came back up (could ping it), but I found I couldn't ssh in. This turned out to be a separate problem to do with /dev/null (might have gotten broken at the same time). I was able to ssh in using a separate rescue system and apply this fix: http://thesystemadministrator.net/linux-administration/sshd-deamon-failing-to-start
Do not bother trying to fix it. Use boot-repair Connect to the internet, then open a terminal with Ctrl+Alt+t, paste the following commands and run them by pressing Enter:
The next (dangerous) thing you can do if boot-repair did not work is try to reinstall which is will not let you. So choose something else. Create everything the same and have the same password and username. This has been said to work as a repair.
Better alternative if boot-repair does not work is to backup your data and fresh install. You can backup with a live disk. I remember I did something trivial in Lubuntu that only messed up some settings. It was suggested to backup and fresh install. I was told it would take an hour to do and not to spend hours trying to figure it out. I ended up following this advice after trying some other things. He was right.
You can also try this link for repairing grub from a live usb https://community.linuxmint.com/tutorial/view/245 I tried something similar (but not the same link) when a failed kernel upgrade messed everything up. I googled "how to fix grub after failed linux upgrade" and got a variety of pages. You might try searching for "grub repair usb live". Try this which has terminal and graphical answers. http://www.howtogeek.com/114884/how-to-repair-grub2-when-ubuntu-wont-boot/
Have you tried grub-install ?
If you can't use it then...
As I see you can run a terminal in the system:
Do
As super user.
The if it didn't ask to install anything then nothing is broken.
Consider :
Last
Now try again with grub-install
Note:
For grub-install usage do:
This would be sufficient as root in recovery-mode after network is enabled :
For partition you type the booting partition which you are very secure of like for example /dev/sda
Then do this following:
There is spell-checking error but only slightly ? You could try this :
and NOT