Rebuild the official Ubuntu kernel – Ubuntu 16.04 LTS

There are multiple reasons to rebuild the official kernel of a Linux distro but this is not the purpose of this article

just cannot miss the chance to write that all the kernels are built therefore optimized for the very first 64bit Intel/AMD processor! But come on who wants the most important piece of software to be optimized not for his new and expensive processor but for one released 15 years ago???

. Here we are going to show you how to recompile the latest official Ubuntu kernel of Ubuntu 16.04 LTS – the one, which comes with the apt packages system, because this kernel comes with the latest and greatest patches of the Ubuntu team. You should not confuse this howto with the one, which compile a vanilla kernel or the mainline kernel from So if you want a new kernel or the latest from this is the right tutorial for Ubuntu – Build your own kernel under Ubuntu using mainline (latest) kernel. The official latest kernel in the Ubuntu repository is not always the latest one from, but you can be sure it is probably most secure one, because there are additional modifications, configurations and tests by the team. Here you can see what versions of the kernel are the officials in Ubuntu:

Keep on reading!

megacli – restart a rebuild with a disk in failed state

Sometimes we need to start a rebuild with a disk in failed state when using a LSI hardware controller, but if we just return the good state of the failed disk, it will return immediately in the array and our filesystem will be broken for sure! In addition it happens that when we replace a disk the new disk to be in failed state, too.

So here are simple and tested steps for proper resetting a failed state of a disk to a good state and starting a rebuild. In the example below the disk in failed state is [32:1], replace with the proper [enclosure_id:slot_id] in your case.

  1. Make “Failed State” in “Unconfigured(BAD)”
    megacli -pdmarkmissing -physdrv[32:1] -aAll
  2. Prepare for removal (this command could fail, not a critical one)
    megacli -pdprprmv -physdrv[32:1] -a0
  3. Make the state of the disk “Unconfigured(Good), Spun Up”
    megacli -PDMakeGood -PhysDrv[32:1] -a0
  4. Start rebuild (this command could fail) – if the command fails continue with the next step, if not, the rebuild is restarted successfully.
    megacli -PDRbld -Start -PhysDrv[32:1] -a0


    megacli -pdlocate -start -physdrv[32:1] -a0

    One of the two commands will probably start the rebuild, but if the two fail then continue to the next step.

  5. Start rebuild, first clean the foreign configuration and then make the device hot spare (only if 4 the above command failed)
    megacli -CfgForeign -Clear -aALL
    #set global hostspare
    megacli -PDHSP -Set -PhysDrv [32:1] -a0

* If you need to unset/remove a global hotspare:

megacli -PDHSP -Rmv -PhysDrv [32:1] -aN