I am preparing for hardware upgrades for PowerEdge 1950 Gen II, PowerEdge 2950 Gen II servers and PowerEdge r710 within our DC. They all run Ubuntu 16.04 LTS.
The upgrades involve upgrades of RAM and replace the CPUs in the following order:
- PE1950 – 8gb ram to 32gb ram, Intel Xeon E5335 to Intel Xeon E5450
- PE2950 – 8gb ram to 32gb ram, Intel Xeon 5160 to Intel Xeon E5450
- PEr710 – 8gb ram to 32gb ram, Intel Xeon E5520 to Intel Xeon L5630
As you can notice the hardware change is substantial and would like to ask if it would be best practice to reinstall Ubuntu 16.04 past the upgrades.
I know that Ubuntu would still run, but I have my doubts that the kernel compiled for the old cpus (during the install) would be supporting the new CPUs in full (e.g. microcode, power management, c-states, etc.) For instance the Intel Xeon E5335 had no power management adversus the E5450. SWAP is another issue that is being updated to meet the size of the new memory.
Your opinion matters to me.
Best Answer
No, you do not need to reinstall. You need to rebuild the initramfs, though (run "update-initramfs -u -kall" as root) after you boot with the new processor, to give the intel-microcode package a chance to detect and install the required microcode update for your new processor. Then you need to reboot again to activate any relevant microcode updates.
Please ensure you updated the system firmware (UEFI/BIOS) to the latest available before you update the RAM and processor.
Note that depending on the version of Ubuntu, it will ship a known-broken version of iucode-tool that cannot automatically handle "mixed stepping" systems (where you have two Xeon processors with different steppings in the same system). In that case, you will have to do some manual configuration in /etc/default/intel-microcode.