Author: David (Page 21 of 24)

Intel Skylake/Kaby Lake processors: broken hyper-threading

June 26, 2017 / David / 0 Comments

Overview

Source : https://lists.debian.org/debian-devel/2017/06/msg00308.html

It appears some Intel Xeon CPU’s are susceptible to a recently discovered Hyper Threading bug. However, these are limited to E3 v5/v6 based Xeon systems which are found mostly in entry level servers with single socket implementations. > Dual socket systems currently leverage E5 based Xeons which don’t appear to be affected.

Currently, the easiest way to mitigate against this bug is to simply disable hyper-threading. The bug also appears to be OS agnostic.

Just Servers?

The focus around social media has predominately been around run of the mill servers; ones you typically purchase from the likes of Dell, HP, etc. However, there could be many bespoke devices that leverage susceptible processors, such as NAS/SAN heads. It is unlikely that in the event you find such a device HT can simply be disabled, but it should be something to be aware of.

List of Intel processors code-named “Skylake”
List of Intel processors code-named “Kaby Lake”

Homelab v2 – Part 1

May 19, 2017 / David / 0 Comments

Out with the old

My previous homelab, although functional was starting to hit the limits of 32GB of RAM, particularly when running vCenter, vSAN, NSX, etc concurrently.

A family member had use for my old lab so I decided to sell it and get a replacement whitebox.

Requirements

Quiet – As this would live in my office and powered on pretty much 24/7 it need a silent running machine
Power efficient – I’d rather not rack up the electric bill.
64GB Ram Support

Nice to have

10GbE
IPMI / Remote Access
Mini-ITX

Order List

I’ve had a interest in the Xeon-D boards for quite some time, the low power footprint, SRV-IO support, integrated 10GbE, IPMI and 128GB RAM support make it an attractive offering. I spotted a good deal and decided to take the plunge on a Supermicro X10SDV-4C+-TLN4F

As for a complete list:

Motherboard – Supermicro X10SDV-4C+-TLN4F

RAM – 64GB (4x16GB) ADATA DDR4

Case – TBC, undecided between a supermicro 1U case or a standard desktop ITX case

Network – Existing gigabit switch. 10GbE Switches are still quite expensive, but it’s nice to have future compatibility on the motherboard for it.

I’ve yet to take delivery of all the components, part 2 will include assembly.

VCAP6 Deploy Passed

May 6, 2017 / David / 1 Comment

Now I can rest…

I decided at around mid December to make passing the VCAP6 DCV Deploy exam a target. Today I can tick that objective off. As I have previously passed the VCAP5-DCD exam this should entitle me to the VCIX-DCV certification, but I may need to wait a bit for that.

My Experience

Precisely this time last year I passed the VCAP5-DCD exam. By cheer coincidence I picked exactly 365 days later to do the deploy exam on v6. I was quite nervous as I’ve never done a deploy VMware lab exam before. The lab itself was reasonably well laid out but the response times and general feel of the environment was a bit sluggish, but then again my home lab resides on SSD storage so perhaps I’m used to a snappy interface.

Tips based on my own prep

The study guide from vJenner is an absolute goldmine : http://www.vjenner.com/vcap6-dcv-deployment-study-guide/.
As with all VMware exams the blueprint is your main reference. If you’re comfortable with most of the objectives you should be good to go.
- Additionally, there is a lot to cover. Naturally like myself you’re most likely going to have weak and strong areas. Don’t get too hung of up on (for example) nailing to commit the entire esxcli CLI namespace to memory.
If you’re finding it difficult to fully remember esxcli commands in their entirety remember there’s –help and –example flags.
use a VMware HOL (Hands on Lab) to get acquainted with the UI

Good Luck!

VMW-LGO-CERT-ADV-PRO-6-DATA-CTR-VIRT-DEPLOY-K