Can I delete "generic" kernel if I use "low latency"?

Question

I currently can't update my release as there is not enough space on boot. I just have the one kernel version there, but seem to have both the Generic and Low Latency versions. uname -r just shows

3.8.0-32-lowlatency

ls -lah /boot shows

-rw-r--r--  1 root root 899K Oct  2 00:00 abi-3.8.0-32-generic
-rw-r--r--  1 root root 899K Oct  7 09:27 abi-3.8.0-32-lowlatency
-rw-r--r--  1 root root 152K Oct  2 00:00 config-3.8.0-32-generic
-rw-r--r--  1 root root 152K Oct  7 09:27 config-3.8.0-32-lowlatency
drwxr-xr-x  3 root root 2.0K Jan  1  1970 efi
drwxr-xr-x  5 root root 1.0K Oct 22 10:05 grub
-rw-r--r--  1 root root  32M Oct 22 09:51 initrd.img-3.8.0-32-generic
-rw-r--r--  1 root root  32M Oct 22 10:05 initrd.img-3.8.0-32-lowlatency
drwxr-xr-x  2 root root  12K Feb 25  2013 lost+found
-rw-r--r--  1 root root 173K Dec  5  2012 memtest86+.bin
-rw-r--r--  1 root root 175K Dec  5  2012 memtest86+_multiboot.bin
-rw-------  1 root root 3.0M Oct  2 00:00 System.map-3.8.0-32-generic
-rw-------  1 root root 3.0M Oct  7 09:27 System.map-3.8.0-32-lowlatency
-rw-------  1 root root 5.2M Oct  2 00:00 vmlinuz-3.8.0-32-generic
-rw-------  1 root root 5.2M Oct  7 09:27 vmlinuz-3.8.0-32-lowlatency

So what can I do to allow me to update? Apparently I need 174m on boot and am 40m short.

Unfortunately not. The answers to that post don't apply to this question. — Webalistic, Oct 22 '13 at 10:02
Do you really need the -lowlatency kernel? If not, you can just remove it to free up space: sudo apt-get remove --purge linux-image-3.8.0-32-lowlatency linux-headers-3.8.0-32-lowlatency. — ergysdo, Oct 22 '13 at 10:08
That's kind of the whole question. System Information shows Low Latency as the one being used as does uname -r. In the hd root initrd.img.old links to the generic kernel. So it it safe to remove the generic kernel or will it kill my machine? — Webalistic, Oct 22 '13 at 11:13

score 4 · Answer 1 · answered Sep 30 '17 at 22:24

Yes, if you are only ever using the low latency kernel, and it is working and the packages for it are installed, then you can remove the packages that provide the generic kernel. You might prefer not to, but if you need space in /boot and removing old kernels is insufficient, this is reasonable. Nothing bad is likely to happen, except that if you decide you want to run the generic kenrel then you'll have to install it first.

You've checked that you actually are running the low latency kernel, and that the version number matches kernel packages you have installed, by checking the output of uname -r. So it's fine to remove the -generic packages. Be careful to avoid removing more packages than you intend.

You should also make sure that you will receive updates to your low latency kernel. The linux-lowlatency package, which is a metapackage, declares dependencies on the most recent low latency kernel packages for your Ubuntu release; I recommend you install that unless you know you do not want it (and why). If you just want the kernel but not the header files for it then you can install the linux-image-lowlatency metapackage but not linux-lowlatency.

If you're using the LTS Enablement Stack with a low latency kernel then you'll want the metapackage shown in those instructions for your release, just with lowlatency instead of generic.

Finally, note that most users will prefer the generic kernel, so as errikos suggests, you might consider the alternative of switching back to generic unless you have a specific reason you need to sacrifice other performance characteristics for low latency. See Why choose a low latency kernel over a generic or realtime one? If you do switch back, I recommend you ensure the necessary generic packages are installed and reboot to test that at least one generic kernel that you have installed is actually working (it should be! but try just in case) before you uninstall the lowlatency kernels.

Can I delete "generic" kernel if I use "low latency"?

1 Answers1