Server Admin Guide: A Tale of Two Servers: BIOS, GPU, and NUMA Tuning for XCP-ng: Preserving the valuable work done by Tobias Kreidl (@tjkreidl)

johnnezero

WHAT: This post is dedicated to preserving the valuable server administration guide content produced by @tjkreidl, originally titled "A Tale of Two Servers." These articles were first published in 2019 on the Citrix Blogs, which are unfortunately no longer available.

KUDOS: Special thanks to @john.c for performing some incredible web sleuthing to recover this content, and to @tjkreidl for creating these essential guides in the first place â€” as well as for "Breathing Life" back into them by highlighting their importance before they disappeared forever into the ferocious "Bit-Bucket."

Series Overview & Quick Reference

If you're looking for a high-level summary of the concepts covered in this series — including specific XCP-ng/XO commands for BIOS power management, GPU scheduling, and NUMA inspection — start here:
Quick Reference & Summary Guide

The Complete Series

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Part 1: How BIOS Settings Can Affect Your Apps and GPU Performance:

A deep dive into CPU Power Management (OS DBPM vs. System DBPM) and Turbo mode.
Read Article

Part 2: GPU Settings and Advanced BIOS Tuning

Exploring Uncore frequency, C1E states, and NVIDIA GPU Scheduler modes (Best Effort vs. Equal Share).
Read Article

Part 3: NUMA, CPUs, Sockets/Cores, and VM Performance

Understanding vNUMA, vCPU oversubscription, and the importance of VM startup order for optimal memory placement.
Read Article

Archived for the XCP-ng community. Questions or additional insights? Please discuss below!

poddingue

This is great to see, thank you for taking the time to rescue this; and thanks to @john.c for the recovery work and to @tjkreidl for writing it in the first place.
I went looking, and there is a small XCP-ng-specific piece on this in the official docs under NUMA affinity (https://docs.xcp-ng.org/compute#numa-affinity), but it's nothing like the depth of the Tale of Two Servers series, so having the originals archived is genuinely useful.
I won't pretend to judge how much of the 2019 BIOS and GPU-scheduler guidance still maps cleanly onto current hardware and XCP-ng versions; others here will know where it's aged and where it hasn't.
I'll make sure this is on our radar on the docs side, because it keeps coming up. Really appreciate you keeping this from disappearing.

johnnezero

@poddingue Thank you!
"Anything and Everything we can to to improve XCP-ng", is the "Name of the Game"

tjkreidl

@poddingue said:

This is great to see, thank you for taking the time to rescue this; and thanks to @john.c for the recovery work and to @tjkreidl for writing it in the first place.
I went looking, and there is a small XCP-ng-specific piece on this in the official docs under NUMA affinity (https://docs.xcp-ng.org/compute#numa-affinity), but it's nothing like the depth of the Tale of Two Servers series, so having the originals archived is genuinely useful.
I won't pretend to judge how much of the 2019 BIOS and GPU-scheduler guidance still maps cleanly onto current hardware and XCP-ng versions; others here will know where it's aged and where it hasn't.
I'll make sure this is on our radar on the docs side, because it keeps coming up. Really appreciate you keeping this from disappearing.

Thank you kindly for your positive comments and appreciation. To me, it's amazing how some information can stay relevant for long periods of time, even given the rapid state of evolution in the technology sectors. I will try to get the full HTML docs uploaded soon, as well. There are a number of other XenServer articles I discovered a while back on a Polish server, and will see what else I can retrieve.
My original avocation for 15 years was that of an astronomer, so research is in my blood and diving into specific issues and doing extensive testing have always been a big part of my motivation to better understand as well as share knowledge.

tjkreidl

I tried adding the HTML file bundles and made a horrible mess, which took forever for me to clean up. The on-line instructions were not very helpful. What I saved as files seemed to contain also way more stuff than it should have, some seemingly unrelated to the original blog. Sigh. I'm no Github expert, that's for sure.

poddingue

That GitHub HTML-bundle pain is real, especially when whatever exported the pages dragged in half the surrounding site CSS and sidebar widgets along with the article. You spent the time writing the originals; the file-wrangling shouldn't be what costs you another evening.

If it's useful, I'm up for taking the cleanup off your hands. Concretely:

pull the HTML you saved from the repo (or a zip / branch you point me at)
strip out the noise: scripts, sidebars, navigation, anything that isn't the article body and its images
convert to markdown, one file per article, images kept alongside
open a PR against tobiaskreidl/Citrix-Tobias-Kreidl-Collection (https://github.com/tobiaskreidl/Citrix-Tobias-Kreidl-Collection) so you stay the owner and only have to review and merge

If the saved bundles are too far gone, I'd fall back to the Citrix URLs @john.c surfaced and pull clean copies via the Wayback Machine. Same end result on your repo.

Separately, and only if that lands cleanly, I'd love to talk to Thomas Moraine and the docs team at Vates about whether parts of this could find a home on docs.xcp-ng.org, linked back to your repo with full credit. The NUMA-affinity page I pointed at earlier is shallow next to what you wrote, and the BIOS / GPU-scheduler material has no current equivalent at all. Whether the 2019 specifics still map cleanly onto current XCP-ng versions and hardware is a separate conversation; even as an archived reference, it's more than what's there today.

No pressure, no obligation. If you'd rather keep iterating on the repo yourself, that's fine too. But if a clean-the-HTML-and-PR-it pass would save you a week of GitHub-tool frustration, I'm genuinely up for it. Just point me at the bundle.