Plus Jim's journeys with Clear Linux, and why Ubuntu 18.04.4 is a maintenance release worth talking about.

Links:

• Ubuntu 18.04.4 LTS: here's what's new — It's not as shiny and exciting as entirely new versions, of course, but it does pack in some worthwhile security and bugfix upgrades, as well as support for more and newer hardware.
• 18.04.4 - Ubuntu Wiki
• MobaXterm — Enhanced terminal for Windows with X11 server, tabbed SSH client, network tools and much more.
• Linux distro review: Intel’s own Clear Linux OS — There's not much question that Clear Linux is your best bet if you want to turn in the best possible benchmark numbers. The question not addressed here is, what's it like to run Clear Linux as a daily driver? We were curious, so we took it for a spin.
• Clear Linux* Project — Clear Linux OS is an open source, rolling release Linux distribution optimized for performance and security, from the Cloud to the Edge, designed for customization, and manageability.
• swupd — Documentation for Clear Linux* project
• clr-boot-manager: Kernel & Boot Loader Management
• Cannot compile zfs for 5.5-rc2 · Issue #9745 · zfsonlinux/zfs
• Persistent L2ARC might be coming to ZFS on Linux — The primary ARC is kept in system RAM, but an L2ARC device can be created from one or more fast disks. In a ZFS pool with one or more L2ARC devices, when blocks are evicted from the primary ARC in RAM, they are moved down to L2ARC rather than being thrown away entirely. In the past, this feature has been of limited value, both because indexing a large L2ARC occupies system RAM which could have been better used for primary ARC and because L2ARC was not persistent across reboots.
• Persistent L2ARC by gamanakis · Pull Request #9582 · zfsonlinux/zfs — This feature implements a light-weight persistent L2ARC metadata structure that allows L2ARC contents to be recovered after a reboot. This significantly eases the impact a reboot has on read performance on systems with large caches.
• LINUX Unplugged 303: Stateless and Dateless — We visit Intel to figure out what Clear Linux is all about and explain a few tricks that make it unique.
• LINUX Unplugged Blog: Clear Linux OS 2019
• HAMR don’t hurt ’em: laser-assisted hard drives are coming in 2020 — Although the 2012 "just around the corner" HAMR drives seem to have been mostly vapor, the technology is a reality now. Seagate has been trialing 16TB HAMR drives with select customers for more than a year and claims that the trials have proved that its HAMR drives are "plug and play replacements" for traditional CMR drives, requiring no special care and having no particular poor use cases compared to the drives we're all used to.
• HAMR Milestone: Seagate Achieves 16TB Capacity on Internal HAMR Test Units
• Western Digital debuts 18TB and 20TB near-MAMR disk drives
• Previously on TechSNAP 341: HAMR Time — We've got bad news for Wifi-lovers as the KRACK hack takes the world by storm; We have the details & some places to watch to make sure you stay patched. Plus, some distressing revelations about third party access to your personal information through some US mobile carriers. Then we cover the ongoing debate over HAMR, MAMR, and the future of hard drive technology & take a mini deep dive into the world of elliptic curve cryptography.

Plus we turn our eye to hardware and get excited about the latest Ryzen line from AMD.

Links:

• Third parties confirm AMD’s outstanding Ryzen 3000 numbers | Ars Technica — AMD debuted its new Ryzen 3000 desktop CPU line a few weeks ago at E3, and it looked fantastic. For the first time in 20 years, it looked like AMD could go head to head with Intel's desktop CPU line-up across the board. The question: would independent, third-party testing back up AMD's assertions?
• The Internet broke today: Facebook, Verizon, and more see major outages | Ars Technica — Last week, Verizon caused a major BGP misroute that took large chunks of the Internet, including CDN company Cloudflare, partially down for a day. This week, the rest of the Internet has apparently asked Verizon to hold its beer.
• It was a really bad month for the internet | TechCrunch — In the past month there were several major internet outages affecting millions of users across the world. Sites buckled, services broke, images wouldn’t load, direct messages ground to a halt and calendars and email were unavailable for hours at a time.
• Cloudflare outage caused by bad software deploy (updated) — For about 30 minutes today, visitors to Cloudflare sites received 502 errors caused by a massive spike in CPU utilization on our network. This CPU spike was caused by a bad software deploy that was rolled back.
• How Verizon and a BGP Optimizer Knocked Large Parts of the Internet Offline Today — Today at 10:30UTC, the Internet had a small heart attack. A small company in Northern Pennsylvania became a preferred path of many Internet routes through Verizon (AS701), a major Internet transit provider.
• Getting started | Prometheus — This guide is a "Hello World"-style tutorial which shows how to install, configure, and use Prometheus in a simple example setup.
• prometheus/node_exporter — Prometheus exporter for hardware and OS metrics exposed by *NIX kernels, written in Go with pluggable metric collectors.
• Using netdata with Prometheus — Prometheus is a distributed monitoring system which offers a very simple setup along with a robust data model. Recently netdata added support for Prometheus.
• prometheus/nagios_plugins — Nagios plugin for alerting on prometheus query results.
• RobustPerception/nrpe_exporter — The NRPE exporter exposes metrics on commands sent to a running NRPE daemon.
• m-lab/prometheus-nagios-exporter — The Prometheus Nagios exporter reads status and performance data from nagios plugins via the MK Livestatus Nagios plugin and publishes this in a form that can be scrapped by Prometheus.
• Comparison to alternatives | Prometheus — Prometheus is a full monitoring and trending system that includes built-in and active scraping, storing, querying, graphing, and alerting based on time series data.
• Quality server monitoring solution using NetData/Prometheus/Grafana — I’m going to quickly show you how to install both netdata and Prometheus on the client and server. We can then use grafana pointed at Prometheus to obtain long-term metrics netdata offers.
• Monitoring stack by using Grafana + Prometheus + Netdata — This monitoring stack you can monitoring in real-time by Netdata and see the history by using Grafana.
• Monitoring Agent · NCPA — New to NCPA? See some of the awesome features present in the Web GUI and API, available on any operating system.
• Nagios 101: Understanding the Fundamentals - Nagios
• Nagios Documentation

Plus the right way to setup PHP, the trouble with benchmarking, and when to choose NGiNX.

Links:

• Jim's Blog: Installing WordPress on Apache the modern way — It’s been bugging me for a while that there are no correct guides to be found about using modern Apache 2.4 or above with the Event or Worker MPMs. We’re going to go ahead and correct that lapse today, by walking through a brand-new WordPress install on a new Ubuntu 18.04 VM.
• Apache Performance Tuning — Apache 2.x is a general-purpose webserver, designed to provide a balance of flexibility, portability, and performance. Although it has not been designed specifically to set benchmark records, Apache 2.x is capable of high performance in many real-world situations.
• Tuning Your Apache Server
• worker - Apache HTTP Server Version 2.4 — This Multi-Processing Module (MPM) implements a hybrid multi-process multi-threaded server. By using threads to serve requests, it is able to serve a large number of requests with fewer system resources than a process-based server.
• event - Apache HTTP Server Version 2.4 — The event Multi-Processing Module (MPM) is designed to allow more requests to be served simultaneously by passing off some processing work to the listeners threads, freeing up the worker threads to serve new requests.
• PHP-FPM — PHP-FPM (FastCGI Process Manager) is an alternative PHP FastCGI implementation with some additional features useful for sites of any size, especially busier sites.
• FastCGI overview — FastCGI is a way to have CGI scripts execute time-consuming code (like opening a database) only once, rather than every time the script is loaded. In technical terms, FastCGI is a language independent, scalable, open extension to CGI that provides high performance without the limitations of server specific APIs.
• Alexa Top 500 Global Sites
• What Is a CDN? How Does a CDN work? — A content delivery network (CDN) refers to a geographically distributed group of servers which work together to provide fast delivery of Internet content.
• W3 Total Cache – WordPress plugin — W3 Total Cache improves the SEO and user experience of your site by increasing website performance, reducing load times via features like content delivery network (CDN) integration and the latest best practices.
• krakjoe/apcu: APCu - APC User Cache — APCu is an in-memory key-value store for PHP. Keys are of type string and values can be any PHP variables.
• PHP: APCu - Manual
• Introduction to Varnish — Varnish HTTP Cache — Varnish Cache is a web application accelerator also known as a caching HTTP reverse proxy. You install it in front of any server that speaks HTTP and configure it to cache the contents. Varnish Cache is really, really fast. It typically speeds up delivery with a factor of 300 - 1000x, depending on your architectur
• ab - Apache HTTP server benchmarking tool — ab is a tool for benchmarking your Apache Hypertext Transfer Protocol (HTTP) server. It is designed to give you an impression of how your current Apache installation performs. This especially shows you how many requests per second your Apache installation is capable of serving.
• HTTP(S) Benchmark Tools
• jimsalterjrs/network-testing — This is a small collection of GPLv3-licensed tools to assist an intrepid researcher in testing the performance of networks, wired or wireless.

Plus a concise breakdown of Meltdown, Spectre, and side-channel attacks like only TechSNAP can.

Then we run through the timeline of events, and the scuttlebutt of so called coordinated disclosure. We also discuss yet another security issue in macOS High Sierra, a backdoor in popular storage appliances, your questions, and more!

Sponsored By:

• Ting: Save $25 off a device, or get $25 in service credits! Promo Code: Visit techsnap.ting.com
• iXSystems: Get a system purpose built for you. Promo Code: Tell them we sent you!
• Digital Ocean: Apply our promo snapocean after you create your account, and get a $10 credit. Promo Code: snapocean

Links:

• Meltdown and Spectre — Meltdown and Spectre exploit critical vulnerabilities in modern processors.
• The Meltdown and Spectre CPU Bugs, Explained
• How we got to Spectre and Meltdown A Timeline My version of the timeline... — My version of the timeline on Spectre Meltdown. This post will be updated! If you want to add/correct something, please comment.
• How Tier 2 cloud vendors banded together to cope with Spectre and Meltdown | TechCrunch — Eventually six cloud providers — Scaleway, DigitalOcean, Packet, Vultr, Linode and OVH — formed a consortium of sorts to help one another and share information. In order to make the process more efficient, they started a Slack channel with CEOs, CTOs and engineers from the various companies sharing information and fixes as they became available.
• FreeBSD was made aware of Meltdown and Spectre in late December. There's currently no ETA for mitigation. — It looks like Dragonfly BSD has a patch, so hopefully that will be useful for FreeBSD.
• heads up: Fix for intel hardware bug will lead to performance regressions — Upcoming versions of the linux kernel (and apparently also windows and others), will include new feature that apparently has been implemented with haste to work around an intel hardware bug.
• AWS Developer Forums: Degraded performance — Immediately following the reboot my server running on this instance started to suffer from cpu stress.
• Google is pushing Retpoline — With Retpoline, we could protect our infrastructure at compile-time, with no source-code modifications. Furthermore, testing this feature, particularly when combined with optimizations such as software branch prediction hints, demonstrated that this protection came with almost no performance loss.
• PCID is now a critical performance/security feature on x86 — On any system that does not currently show "pcid" in the flags line of /proc/cpuinfo, Meltdown is a bigger issue than "install latest updates".
• Spectre & Meltdown vulnerability/mitigation checker for Linux — A simple shell script to tell if your Linux installation is vulnerable against the 3 "speculative execution" CVEs that were made public early 2018.
• Microsoft PowerShell Script to check for Meltdown — To help customers verify that protections are enabled, Microsoft has published a PowerShell script that customers can run on their systems. Install and run the script by running the following commands.
• Why Raspberry Pi isn't vulnerable to Spectre or Meltdown — To help us understand why, here’s a little primer on some concepts in modern processor design.
• macOS High Sierra's App Store System Preferences Can Be Unlocked With Any Password — A bug report submitted on Open Radar this week has revealed a security flaw in the current version of macOS High Sierra that allows the App Store menu in System Preferences to be unlocked with any password.
• Major macOS High Sierra Bug Allows Full Admin Access Without Password
• WD My Cloud NAS devices have hard-wired backdoor — Lets anyone log in as user mydlinkBRionyg with the password abc12345cba.
• Question: How could I measure all of these overhead performance hits? — My question: how could I measure all of these overhead performance hits, so I can put in a well educated request to adjust all of these components, so I have a computer that performs near its capacity?
• Perfmon
• Troubleshooting with the Windows Sysinternals Tools
• ProcDump
• Process Monitor - Replaces filemon
• Question: MySQL Replication Woes — The problem is that during some larger deletes on the master, the tables on the slave get locked and the slave lag goes through the roof.. During this time all of my selects that have been sent to the slave are just sitting there and waiting for the table to unlock while the master is just fine.
• Ask Noah 44: Red Hat with Brandon Johnson
• BSD Now 228: The Spectre of Meltdown