Question #267005 “What happens when the /boot partition is full?...” : Questions : Ubuntu

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actionparsnip (andrew-woodhead666) said on 2015-05-16:

#1

When the /boot partition fills you cannot install more kernels. The old kernels are kept to allow users to boot to older kernels if a new one causes an issue. I agree it's annoying and users having to manually remove lots of ancient kernels is stupid.

You could report a bug, maybe the postinst script could uninstall all but the last 3 kernels (as an option in settings)

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Manfred Hampl (m-hampl) said on 2015-05-17:

#2

What Ubuntu release are you running?
Since 14.04 the old kernels are marked as 'no more required', such that they can be easily removed with the command

sudo apt-get --purge autoremove

And back to your original question:

The only effect of a full /boot partition is that new kernels can no more be installed. Everything else (cron, etc.) should happen outside the /boot partition and should not be affected (as long as there is enough free space on the root partition / )

I would not recommend to disable updates, because bug fixes are delivered via that mechanism. Think back a few weeks to shellshock, heartbleed, ...

What is the output of the terminal commands

uname -a
lsb_release -crid
dpkg -l | egrep ' linux-[hi]'
df -h
df -i

This should provide some information about your system and might help in giving more answers.

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actionparsnip (andrew-woodhead666) said on 2015-05-17:

#3

Ubuntu Tweak can do it for you. I know guys with a cron job to do the job.

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tearsforhari (tearsforhari) said on 2015-05-19:

#4

Manfred, here are the outputs:
> uname -a
Linux MachineName 3.5.0-45-generic #68~precise1-Ubuntu SMP Wed Dec 4 16:18:46 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

>lsb_release -crid
Distributor ID: Ubuntu
Description: Ubuntu 12.04.5 LTS
Release: 12.04
Codename: precise

>dpkg -l | egrep ' linux-[hi]'ii linux-headers-3.5.0-39 3.5.0-39.60~precise1 Header files related to Linux kernel version 3.5.0
ii linux-headers-3.5.0-39-generic 3.5.0-39.60~precise1 Linux kernel headers for version 3.5.0 on 64 bit x86 SMP
ii linux-headers-3.5.0-45 3.5.0-45.68~precise1 Header files related to Linux kernel version 3.5.0
ii linux-headers-3.5.0-45-generic 3.5.0-45.68~precise1 Linux kernel headers for version 3.5.0 on 64 bit x86 SMP
ii linux-headers-3.5.0-46 3.5.0-46.70~precise1 Header files related to Linux kernel version 3.5.0
ii linux-headers-3.5.0-46-generic 3.5.0-46.70~precise1 Linux kernel headers for version 3.5.0 on 64 bit x86 SMP
ii linux-headers-3.5.0-47 3.5.0-47.71~precise1 Header files related to Linux kernel version 3.5.0
ii linux-headers-3.5.0-47-generic 3.5.0-47.71~precise1 Linux kernel headers for version 3.5.0 on 64 bit x86 SMP
ii linux-headers-3.5.0-54 3.5.0-54.81~precise1 Header files related to Linux kernel version 3.5.0
ii linux-headers-3.5.0-54-generic 3.5.0-54.81~precise1 Linux kernel headers for version 3.5.0 on 64 bit x86 SMP
ii linux-headers-generic-lts-quantal 3.5.0.54.59 Generic Linux kernel headers
ii linux-image-3.5.0-45-generic 3.5.0-45.68~precise1 Linux kernel image for version 3.5.0 on 64 bit x86 SMP

>df -h
/dev/mapper/MachineName 21G 12G 7.7G 61% /
udev 989M 4.0K 989M 1% /dev
tmpfs 200M 768K 199M 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 999M 0 999M 0% /run/shm
/dev/sdb1 74G 795M 70G 2% /mnt/2ndHDD
/dev/sda1 228M 29M 187M 14% /boot

> df -I
/dev/mapper/MachineName 1362720 250855 1111865 19% /
udev 253136 454 252682 1% /dev
tmpfs 255538 398 255140 1% /run
none 255538 5 255533 1% /run/lock
none 255538 1 255537 1% /run/shm
/dev/sdb1 4915200 3691 4911509 1% /mnt/2ndHDD
/dev/sda1 124496 232 124264 1% /boot

Manfred, here are the outputs:
> uname -a
Linux MachineName 3.5.0-45-generic #68~precise1-Ubuntu SMP Wed Dec 4 16:18:46 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

>lsb_release -crid
Distributor ID: Ubuntu
Description:    Ubuntu 12.04.5 LTS
Release:        12.04
Codename:       precise

>dpkg -l | egrep ' linux-[hi]'ii  linux-headers-3.5.0-39                 3.5.0-39.60~precise1                    Header files related to Linux kernel version 3.5.0
ii  linux-headers-3.5.0-39-generic         3.5.0-39.60~precise1                    Linux kernel headers for version 3.5.0 on 64 bit x86 SMP
ii  linux-headers-3.5.0-45                 3.5.0-45.68~precise1                    Header files related to Linux kernel version 3.5.0
ii  linux-headers-3.5.0-45-generic         3.5.0-45.68~precise1                    Linux kernel headers for version 3.5.0 on 64 bit x86 SMP
ii  linux-headers-3.5.0-46                 3.5.0-46.70~precise1                    Header files related to Linux kernel version 3.5.0
ii  linux-headers-3.5.0-46-generic         3.5.0-46.70~precise1                    Linux kernel headers for version 3.5.0 on 64 bit x86 SMP
ii  linux-headers-3.5.0-47                 3.5.0-47.71~precise1                    Header files related to Linux kernel version 3.5.0
ii  linux-headers-3.5.0-47-generic         3.5.0-47.71~precise1                    Linux kernel headers for version 3.5.0 on 64 bit x86 SMP
ii  linux-headers-3.5.0-54                 3.5.0-54.81~precise1                    Header files related to Linux kernel version 3.5.0
ii  linux-headers-3.5.0-54-generic         3.5.0-54.81~precise1                    Linux kernel headers for version 3.5.0 on 64 bit x86 SMP
ii  linux-headers-generic-lts-quantal      3.5.0.54.59                             Generic Linux kernel headers
ii  linux-image-3.5.0-45-generic           3.5.0-45.68~precise1                    Linux kernel image for version 3.5.0 on 64 bit x86 SMP

>df -h
/dev/mapper/MachineName 21G   12G  7.7G  61% /
udev                             989M  4.0K  989M   1% /dev
tmpfs                            200M  768K  199M   1% /run
none                             5.0M     0  5.0M   0% /run/lock
none                             999M     0  999M   0% /run/shm
/dev/sdb1                         74G  795M   70G   2% /mnt/2ndHDD
/dev/sda1                        228M   29M  187M  14% /boot

> df -I
/dev/mapper/MachineName 1362720 250855 1111865   19% /
udev                             253136    454  252682    1% /dev
tmpfs                            255538    398  255140    1% /run
none                             255538      5  255533    1% /run/lock
none                             255538      1  255537    1% /run/shm
/dev/sdb1                       4915200   3691 4911509    1% /mnt/2ndHDD
/dev/sda1                        124496    232  124264    1% /boot

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Manfred Hampl (m-hampl) said on 2015-05-19:

#5

Ok, thanks for the output.

You are running Ubuntu 12.04, so the command about just running 'sudo apt-get autoremove' will not work for your system. You have to use different mechanisms for cleaning up obsolete kernel packages.

Your /dev/sda1 partition that is the /boot directory has 228 MB size. This enables you to have about five or six kernel packages installed at the same time. It is a common practice to delete all except the two or three newest ones whenever the package updater has installed a new one.

What puzzles me a bit is the fact that I see only one kernel package on your system, which is already one and a half years old. So apparently you currently do not get updates and bug fixes on the kernel image package.

My recommendations:
Install linux-generic-lts-quantal to make sure that you get updates and bug fixes for the kernel image package.
Install ubuntu-tweak from the tualatrix ppa and once a month start ubuntu-tweak and use the janitor function to remove obsolete kernel packages.

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Manfred Hampl (m-hampl) said on 2015-05-20:

#7

I do not have a server and I do not use auto-updates, so I do not have any experience with that.
I update my systems manually.

General answers:

The command "dpkg -l" lists the status of packages on your system. There are different status codes shown in the first column. The most common ones are ii and rc.

ii tells that the package is successfully installed
rc indicates that the packages was installed, has successfully been removed, and just configuration files are left.

If a kernel package has been uninstalled because it has been made obsolete by later versions, then you will never need its configuration files again, and you might clean them up.

All configuration files left over from uninstalled packages can be removed with the command

dpkg -l | grep '^rc' | awk '{print $2}' | xargs sudo dpkg --purge

If you do this on that second system, then re-running "dpkg -l | egrep ' linux-[hi]'" should show only the Linux-image packages installed with versions 3.2.0-60.91, 3.2.0-82.119 and 3.2.0-83.120. This is acceptable. You might think of purging also the 3.2.0-60 version if you are sure that your system has already been rebooted into a newer kernel.

You can avoid that the configuration files are left behind, if you use different parameters or add certain options to the uninstallation command ("sudo apt-get purge packagename" instead of "sudo apt-get remove packagename" or "sudo apt-get remove --purge packagename"; similar for dpkg).

My general advice for all systems (desktops and servers, no difference whether automatic updates are installed or not):

Regularly do housekeeping (frequency should be between once a week and once a month):
issue "sudo apt-get update && sudo apt-get dist-upgrade" to install all available updates (unless they are already installed by automatic updates)
issue the "dpkg -l | egrep ' linux-[hi]'" command to check for the number and versions of installed kernel packages (both headers and image)
use uname -a to verify the version number of the running kernel
if you are not running the newest kernel version, reboot the system (of course you have to choose a suitable moment, not to disturb normal server operations)
when the newest kernel is working without problems purge old kernel image and kernel header packages, leaving only those with the highest two (eventually three) version numbers installed.