remove old kernels through Boot-Repair

[kuv02]

Hi,

I have a problem with "kernel panic-not syncing: VFS: unable to mount root fs on unknown block(0,0)" and could trace it down (through this (http://www.ubuntu-forum.de/artikel/65502/kernel-panic-not-syncing-vfs-unable-to-mount-root-fs-on-unknown-block-0-0.html) threads (http://ubuntuforums.org/showthread.php?t=2302981)) to a full boot partition.

I was told to use Boot-Repair (https://help.ubuntu.com/community/Boot-Repair) to check my system. Boot-Repair is currently the only way I can access my system (I also have a Fedora Live DVD around, but never used it)

I tried to remove old kernels as described in this ubuntu-help Article (https://help.ubuntu.com/community/Lubuntu/Documentation/RemoveOldKernels).
But this does not work, because the article assumes I'm in the system whose kernels I want to clean up. But I am in Boot-Repair. I have no clue how to access the kernels and clean them.

From the boot-repair report (http://paste.ubuntu.com/13441685/) i could see, that I need to mount drives etc. I really would need help with this. I try to fix this problem for 3 weeks.

[kuv02]

This is the content of my boot partition. What shall I delete and How do I do this?

lubuntu@lubuntu:/$ sudo mount -t ext2 /dev/sda1 /mnt/boot-sav/sda1lubuntu@lubuntu:/$ cd /mnt/boot-sav/sda1/
lubuntu@lubuntu:/mnt/boot-sav/sda1$ ls -lp
total 220566
-rw-r--r-- 1 root root 1268815 Apr 17 2015 abi-3.19.0-15-generic
-rw-r--r-- 1 root root 1269284 Mai 19 2015 abi-3.19.0-18-generic
-rw-r--r-- 1 root root 1269462 Mai 29 2015 abi-3.19.0-20-generic
-rw-r--r-- 1 root root 1269462 Jun 14 19:44 abi-3.19.0-21-generic
-rw-r--r-- 1 root root 1270417 Jul 24 23:35 abi-3.19.0-25-generic
-rw-r--r-- 1 root root 1271689 Okt 21 11:54 abi-3.19.0-32-generic
-rw-r--r-- 1 root root 177656 Apr 17 2015 config-3.19.0-15-generic
-rw-r--r-- 1 root root 177700 Mai 19 2015 config-3.19.0-18-generic
-rw-r--r-- 1 root root 177700 Mai 29 2015 config-3.19.0-20-generic
-rw-r--r-- 1 root root 177700 Jun 14 19:44 config-3.19.0-21-generic
-rw-r--r-- 1 root root 177771 Jul 24 23:35 config-3.19.0-25-generic
-rw-r--r-- 1 root root 177782 Okt 21 11:54 config-3.19.0-32-generic
drwxr-xr-x 5 root root 1024 Nov 11 15:41 grub/
-rw-r--r-- 1 root root 30861158 Mai 25 2015 initrd.img-3.19.0-15-generic
-rw-r--r-- 1 root root 30864964 Jun 14 14:45 initrd.img-3.19.0-18-generic
-rw-r--r-- 1 root root 30865915 Jun 14 14:47 initrd.img-3.19.0-20-generic
-rw-r--r-- 1 root root 30865311 Jun 17 19:15 initrd.img-3.19.0-21-generic
-rw-r--r-- 1 root root 30872082 Jul 31 19:56 initrd.img-3.19.0-25-generic
drwx------ 2 root root 12288 Mai 23 2015 lost+found/
-rw-r--r-- 1 root root 164216 Mär 6 2015 memtest86+.bin
-rw-r--r-- 1 root root 165892 Mär 6 2015 memtest86+.elf
-rw-r--r-- 1 root root 166396 Mär 6 2015 memtest86+_multiboot.bin
-rw------- 1 root root 3615358 Apr 17 2015 System.map-3.19.0-15-generic
-rw------- 1 root root 3616263 Mai 19 2015 System.map-3.19.0-18-generic
-rw------- 1 root root 3617303 Mai 29 2015 System.map-3.19.0-20-generic
-rw------- 1 root root 3617303 Jun 14 19:44 System.map-3.19.0-21-generic
-rw------- 1 root root 3617653 Jul 24 23:35 System.map-3.19.0-25-generic
-rw------- 1 root root 3622220 Okt 21 11:54 System.map-3.19.0-32-generic
-rw-r--r-- 1 root root 6611584 Mai 23 2015 vmlinuz-3.19.0-15-generic
-rw------- 1 root root 6614144 Mai 19 2015 vmlinuz-3.19.0-18-generic
-rw------- 1 root root 6616960 Mai 29 2015 vmlinuz-3.19.0-20-generic
-rw------- 1 root root 6617408 Jun 14 19:44 vmlinuz-3.19.0-21-generic
-rw------- 1 root root 6616704 Jul 24 23:35 vmlinuz-3.19.0-25-generic
-rw------- 1 root root 6623936 Okt 21 11:54 vmlinuz-3.19.0-32-generic

[ian-weisser]

Delete any of the 3.19.0-15 files. Those are the oldest.
BUT also replace them with empty files of exactly the same name. The 'touch' command is handy for that.

Those files are placed by the package manager, and must be removed by the package manager; if you simply delete them, you exchange a broken system for a differently-broken system.
The trick here is that the package manager doesn't care at all about the contents or size of the file.

Once your system is bootable, remove those old kernels using the package manager.

[grahammechanical]

If you are getting a Grub boot menu you can go into Advanced Options for Ubuntu and select recovery mode. the recovery menu will give, amongst others, these options


Clean try to make free space
Root drop to a root shell prompt

The file system will be in read only mode. To put it in read/write mode run one of the other options such as Network and then use the root shell prompt to purge kernels as decribed here.

https://help.ubuntu.com/community/Lubuntu/Documentation/RemoveOldKernels

Typing Exit will bring you back to the recovery menu where Resume will try to load to a desktop.

Regards.

[kuv02]

I was pointed out to the possability to boot into older kernels via grubs "Ubuntu advanced boot options". I than removed the unnecessary kernels via the package manager.

[dmtparker]

How do you get into "Ubuntu advanced boot options"? I need to boot into an older kernal (usb3 does not work under latest - see other post) but at least in my version of ubuntu studio (14.04.3) grub is silent and not interactive. I've tried all the usual keys (<shift> <cntrl> <alt> <esc>) to no avail.