kernel upgrades

I was just reading the Linux Kernel Stuff page on the Wiki (http://wiki.brightbox.co.uk/docs:kernel) and noticed the mention of using a 64bit kernel and a 32bit userland, as well as the warning that apt can’t install 64bit kernel packages in a 32bit userland. In the past I’ve allowed kernel upgrades to be installed when I’ve done the usual ‘sudo apt-get update; sudo apt-get upgrade’ – is this going to have resulted in my getting a 32bit kernel? I’m finding it tricky to determine whether my virtual machine is running a 64-bit kernel: ‘uname -a’ includes x86_64 in it’s output, but running ‘file’ on some of the .ko files under /lib/modules says ‘ELF 32-bit LSB relocatable, Intel 80386…’ where on my 64-bit laptop it says ‘ELF 64-bit LSB relocatable, x86-64…’.

If I have inadvertently installed a 32bit kernel, is there a way of repairing the damage?

A couple of other questions cross my mind also:

• Is there any way to select the kernel version that will be booted when the virtual machine is rebooted, as I now have multiple kernels installed?
• Is there a command to clean up the old kernels that I no longer need installed?

Cheers,

-Mark.

Hi Mark,

the kernel is set by our systems, upgrading it from within your machine won’t make any difference – so you’ve done no damage.

To clarify, Brightboxes are 32bit userland, but with 64bit kernels. That is why the kernel says x86_64 but file says libraries are 32bit LSB relocatable. This allows us to use a fast stable 64bit kernel, but not have Ruby (and other processes) waste RAM dealing with 64bit pointers.

Our managed MySQL boxes are 64bit userland, as MySQL benefits from being 64bit more than Ruby/Rails does.