uptime command in Linux

This uptime command guide is a follow-up to my previous 90 Linux Commands frequently used by Linux Sysadmins article. As time allows, I will continue to publish articles on these 90 commands geared toward Linux sysadmins and power users. Let’s continue this series with the uptime command. The uptime outputs the current time, system uptime, number of logged-in […]

btop – the htop alternative

Meet btop, an aesthetically pleasing system resource monitor showing usage and stats for processor, memory, disks, network, and processes. btop is the lighter and faster C++ version and continuation of bashtop and bpytop. Over the years, the available options for command-line system monitoring tools have grown quite a bit. There is top, htop, glances, nmon, ytop, gtop, vtop, and […]

Could not increase number of max_open_files to more than… (Solution)

A quick solution to the warning “Could not increase number of max_open_files to more than” when starting MySQL or MariaDB. For some background, read How MySQL Opens and Closes Tables. Here’s an excerpt: “The table_open_cache and max_connections system variables affect the maximum number of files the server keeps open. If you increase one or both of […]

50 Top ‘Internet of Things’ Security Solutions

A couple of months back, I decided to maintain a list of companies that offer IoT (internet of things) security tools and solutions which you can find below. Feel free to share your solutions, feedback, and tips for securing IoT devices. Going forward, I will update this list continuously. A few key questions arose after […]

How to Kill Inactive SSH Sessions

So, you’ve been disconnected from your server a couple of times, resulting in inactive ssh sessions. You know this because when you use the “w” command, you see something like the following… 22:47:28 up 315 days, 21:09, 2 users, load average: 9.04, 8.17, 7.30 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT root pts/0 ipxxx-xxx-xxx-xxx 23:54 26:40 […]

85% of all Smartphones are powered by Linux

Smartphones powered by Linux are, for a fact, dominating the smartphone market. A few of you may be scratching your heads at this point. Others are filled with “The Sound of Music” – “The Hills are Alive” kind of Linux pride! Read on, and I’ll provide some pudding, filled with proof that 85% of all […]

How to diagnose OOM errors on Linux systems

Out-of-memory (OOM) errors take place when the Linux kernel can’t provide enough memory to run all of its user-space processes, causing at least one process to exit without warning. Without a comprehensive monitoring solution, OOM errors can be tricky to diagnose. In this post, you will learn how to diagnose OOM errors in Linux kernels […]

Linux benchmark scripts and tools

This list of Linux benchmark scripts and tools should prove helpful for quick performance checks of CPU, storage, memory, and network on Linux servers and VPS. Check each script before running from the command line. Most of these scripts will benchmark the CPU, memory, storage, and network. In most cases, the CPU Model, frequency, number […]

Your Web Host Doesn’t Want You To Read This: Benchmark Your VPS

Sept 27th, 2021: Added link to a great list of command-line benckmark scripts. June 17th, 2019: Added instructions for network speed test using speedtest-cli script. Nov 2nd, 2016: Included quick dd commands to check cached vs. uncached read performance. This article will highlight using the ‘dd’ Unix command for a quick benchmark of your Linux […]

atop – For Linux server performance analysis

We’re all familiar with top, a real-time system monitor. Some prefer htop and previously, I mentioned iotop for use with storage read/write monitoring. Let’s looks at another popular tool for Linux server performance analysis: atop.   Advantages of atop Atop is an ASCII full-screen performance monitor which can log and report the activity of all server processes. […]