[CentOS] /boot partition too small

Tue Oct 10 14:17:03 UTC 2017
Pete Biggs <pete at biggs.org.uk>

On Tue, 2017-10-10 at 13:55 +0000, KM wrote:
> First off - let me say I am not an administrator.   I need to know if
> there is an easy way to increase my /boot partition.  When I
> installed CentOS 6 after running 5, it was my oversight not to
> increase the /boot size.  it's too small and I can't do yum updates.

How big is it?

> if it's not easy to actually increase it, is it safe to take a chunk
> in my root filesystem (like /new.boot or something) and just mount it
> as /boot from now on so it uses the space or is that not a good
> idea?  I am sure I could easily copy the rpms/kernel stuff over to it
> and then unmounts the real /boot and mount this new area as /boot.
> Can you administrators let me know what you think of all this?   

No, you can't do that. /boot is special and needs to be a separate

The most likely cause of your problems is that you have multiple
kernels installed - when you boot the machine do you see multiple
versions on the grub boot screen? If you don't need the previous
versions then they can just be deleted using yum: do 'rpm -q kernel' to
see which kernels are installed and 'uname -r' to see which version you
are currently running (it should be the same as the highest version
installed).  You can then use 'yum erase ...' to remove the old
kernels. It's always handy to have a version or two old ones in case of
emergency so I always leave three on a system.

The multiple versions installed of some things - i.e. the kernel - is
controlled by a yum variable in /etc/yum.conf called
'installonly_limit'. It's probably set to 5 at the moment, you can set
it to 3 safely and that is usually sufficient to stop /boot filling up.