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Category Archives for "Networking"

Choosing and changing your Linux shell

There are quite a few shells on Linux system and more that can be easily added. This post examines some of the more popular shells, how they differ and the files that contribute to their configuration.The default shell on most Linux systems is bash. Unless you make an effort, any user accounts added to the system will be assigned bash as their login shell. Bash has been around since 1989 and was meant to replace the Bourne shell (sh). In fact, if you take a look at /bin/sh, you'll probably find that it's nothing more than a symbolic link to /bin/bash.$ ls -l /bin/sh lrwxrwxrwx. 1 root root 4 Jan 25 2021 /bin/sh -> bash Summarizing your command-line usage on Linux   Popular Shells Some of the best and most popular shells include:To read this article in full, please click here

How to choose the best NVMe storage array

Storage will never be as fast as system memory--that’s just the nature of system architecture. But thanks to NVMe (nonvolatile memory express), SSDs can deliver such blazingly fast performance, the penalty of “going to disk” tends to be miniscule.NVMe encompasses a family of specifications for how software talks to storage. It works over a number of transport methods, including PCI Express, RDMA, and TCP. Storage arrays that support the NVMe standard are the sports cars of storage, exposing super-fast storage media more directly and efficiently than any other mainstream method allows.To read this article in full, please click here

Choosing and changing your Linux shell

There are quite a few shells on Linux system and more that can be easily added. This post examines some of the more popular shells, how they differ and the files that contribute to their configuration.The default shell on most Linux systems is bash. Unless you make an effort, any user accounts added to the system will be assigned bash as their login shell. Bash has been around since 1989 and was meant to replace the Bourne shell (sh). In fact, if you take a look at /bin/sh, you'll probably find that it's nothing more than a symbolic link to /bin/bash.$ ls -l /bin/sh lrwxrwxrwx. 1 root root 4 Jan 25 2021 /bin/sh -> bash Summarizing your command-line usage on Linux   Popular Shells Some of the best and most popular shells include:To read this article in full, please click here

How to choose the best NVMe storage array

Storage will never be as fast as system memory--that’s just the nature of system architecture. But thanks to NVMe (nonvolatile memory express), SSDs can deliver such blazingly fast performance, the penalty of “going to disk” tends to be miniscule.NVMe encompasses a family of specifications for how software talks to storage. It works over a number of transport methods, including PCI Express, RDMA, and TCP. Storage arrays that support the NVMe standard are the sports cars of storage, exposing super-fast storage media more directly and efficiently than any other mainstream method allows.To read this article in full, please click here

eBPF: When (and when not) to use it

Extended Berkeley Packet Filter (eBPF) is a relatively new feature for Linux kernels that has many DevOps, SREs, and engineers excited. But is it a one-stop shop solution for all of your Linux kernel needs? Let’s take a look at what eBPF does well, and how it stacks up against standard Linux iptables.

 

What is eBPF?

eBPF is a feature available in Linux kernels that allows you to run a virtual machine inside the kernel. This virtual machine allows you to safely load programs into the kernel, in order to customize its operation. Why is this important?

In the past, making changes to the kernel was difficult: there were APIs you could call to get data, but you couldn’t influence what was inside the kernel or execute code. Instead, you had to submit a patch to the Linux community and wait for it to be approved. With eBPF, you can load a program into the kernel and instruct the kernel to execute your program if, for example, a certain packet is seen or another event occurs.

With eBPF, the kernel and its behavior become highly customizable, instead of being fixed. This can be extremely beneficial, when used Continue reading

ThinkPad X1 Carbon (Gen 7): 2 years later

Two years ago, I replaced my ThinkPad X1 Carbon 2014 with the latest generation. The new configuration embeds an Intel Core i7-8565U, 16 Gib of RAM, a 1 Tib NVMe disk, and a WQHD display (2560×1440). I did not ask for a WWAN card. I think it is easier and more reliable to use the wifi hotspot feature of a phone instead: no unreliable firmware and unsupported drivers.1 Here is my opinion on this model.

ThinkPad X1 Carbon 7th Gen with the lid closed
ThinkPad X1 Carbon with its lid closed

While the second generation got a very odd keyboard, this one got a classic one with a full row of function keys. I don’t know if my model was defective, but the keyboard skips one keypress from time to time. I have got used to it, but the space key still has a hard time registering when hitting it with my right thumb. The travel course is also shorter and it is less comfortable to type on it than it was on the 2014 version. The trackpoint2 works well. The physical buttons are a welcome addition. I am only using the trackpad for scrolling with the two-finger gesture.

Keyboard of the X1 Carbon 7th Gen
Keyboard with an ANSI QWERTY layout (aka English EU for Continue reading

It always takes longer than you think

Everyone is aware that it always takes longer to find a problem in a network than it should. Moving through the troubleshooting process often feels like swimming in molasses—you’re pulling hard, and progress is being made, but never fast enough or far enough to get the application back up and running before that crucial deadline. The “swimming in molasses effect” doesn’t end when the problem is found out, either—repairing the problem requires juggling a thousand variables, most of which are unknown, combined with the wit and sagacity of a soothsayer to work with vendors, code releases, and unintended consequences.

It’s enough to make a network engineer want to find a mountain top and assume an all-knowing pose—even if they don’t know anything at all.
The problem of taking longer, though, applies in every area of computer networking. It takes too long for the packet to get there, it takes to long for the routing protocol to converge, it takes too long to support a new application or server. It takes so long to create and validate a network design change that the hardware, software and processes created are obsolete before they are used.

Why does it always take too long? Continue reading

Intel shifts to multiarchitecture model

There was a time when Intel was all-x86, all the time, everywhere.Not anymore.Last week Intel held its annual Architecture Day with previews of multiple major upcoming architectures beyond x86. For once, it’s not hyperbole when they say these are some of the “biggest shifts in a generation.”CEO Gelsinger shakes up Intel And it’s not just architectures or just more and faster cores, it’s new designs, whole new ways of doing things. Instead of just packing more cores onto a smaller die, Intel is switching to a new hybrid architecture that adds low-energy-draw cores, similar to what some ARM chip makers have been doing for years on mobile devices.To read this article in full, please click here

Intel shifts to multiarchitecture model

There was a time when Intel was all-x86, all the time, everywhere.Not anymore.Last week Intel held its annual Architecture Day with previews of multiple major upcoming architectures beyond x86. For once, it’s not hyperbole when they say these are some of the “biggest shifts in a generation.”CEO Gelsinger shakes up Intel And it’s not just architectures or just more and faster cores, it’s new designs, whole new ways of doing things. Instead of just packing more cores onto a smaller die, Intel is switching to a new hybrid architecture that adds low-energy-draw cores, similar to what some ARM chip makers have been doing for years on mobile devices.To read this article in full, please click here

Network Break 347: Cisco Acquires Container App Monitor; Intel Unwraps Mount Evans IPU

It's the Network Break! This week we analyze Cisco's $500 million acquisition of a container-based and serverless application monitor, Intel's announcement of Mount Evans, an Infrastructure Processing Unit (IPU) for network and storage offload, and more tech news. Guest analyst Johna Till Johnson, CEO and founder of Nemertes Research, joins Greg Ferro.

The post Network Break 347: Cisco Acquires Container App Monitor; Intel Unwraps Mount Evans IPU appeared first on Packet Pushers.

Making Magic Transit health checks faster and more responsive

Making Magic Transit health checks faster and more responsive
Making Magic Transit health checks faster and more responsive

Magic Transit advertises our customer’s IP prefixes directly from our edge network, applying DDoS mitigation and firewall policies to all traffic destined for the customer’s network. After the traffic is scrubbed, we deliver clean traffic to the customer over GRE tunnels (over the public Internet or Cloudflare Network Interconnect). But sometimes, we experience inclement weather on the Internet: network paths between Cloudflare and the customer can become unreliable or go down. Customers often configure multiple tunnels through different network paths and rely on Cloudflare to pick the best tunnel to use if, for example, some router on the Internet is having a stormy day and starts dropping traffic.

Making Magic Transit health checks faster and more responsive

Because we use Anycast GRE, every server across Cloudflare’s 200+ locations globally can send GRE traffic to customers. Every server needs to know the status of every tunnel, and every location has completely different network routes to customers. Where to start?

In this post, I’ll break down my work to improve the Magic Transit GRE tunnel health check system, creating a more stable experience for customers and dramatically reducing CPU and memory usage at Cloudflare’s edge.

Everybody has their own weather station

To decide where to send traffic, Cloudflare edge servers Continue reading

Schneider Electric joins the hardware-as-a-service movement

German data center hardware giant Schneider Electric is the latest OEM to jump on the on-demand leasing program hardware, in this case the company’s American Power Conversion line of uninterruptible power supplies (UPS).The primary beneficiaries are channel partners, but the user comes out ahead as well. This is similar to the on-premises leasing model used by Hewlett Packard Enterprise, Dell Technologies, Lenovo, Cisco, and more. Rather than make a massive up-front purchase, you lease the gear and pay monthly for actual use.The deal is for channel partners to pair APC Smart-UPS solutions with its monitoring and dispatch services to create their own service offering. Schneider says this partnership will allow channel partners to offer more visibility and front-end maintenance across their customers’ dispersed UPS systems.To read this article in full, please click here

Schneider Electric joins the hardware-as-a-service movement

German data center hardware giant Schneider Electric is the latest OEM to jump on the on-demand leasing program hardware, in this case the company’s American Power Conversion line of uninterruptable power supplies (UPS).The primary beneficiaries are channel partners, but the user comes out ahead as well. This is similar to the on-premises leasing model used by Hewlett Packard Enterprise, Dell Technologies, Lenovo, Cisco, and more. Rather than make a massive up-front purchase, you lease the gear and pay monthly for actual use.The deal is for channel partners to pair APC Smart-UPS solutions with its monitoring and dispatch services to create their own service offering. Schneider says this partnership will allow channel partners to offer more visibility and front-end maintenance across their customers’ dispersed UPS systems.To read this article in full, please click here

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