Linux Performance: Why You Should Almost Always Add Swap Space

We know that using Linux swap space instead of RAM (memory) can severely slow down performance. So, one might ask, since I have more than enough memory available, wouldn’t it better to delete swap space? The short answer is, No. There are performance benefits when swap space is enabled, even when you have more than […]

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 […]

Linux Performance: Almost Always Add Swap. Part 2: ZRAM

Previously, we looked at how swap space, particularly swapping, can severely slow down Linux performance. We then tweaked Linux kernel parameters to make better use of server memory and to avoid heavy swapping. That article created some debate and good arguments for and against swap space. For example, if you have more than enough memory […]

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 […]

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. […]

htop: Quick Guide & Customization

htop is an interactive system monitor, but also a process-viewer, process-manager, strace tool and more. Sysadmins may opt to use htop when Unix top does not provide enough information about system processes. htop uses a cursor-controlled interface for sending signals to processes. One example where this comes in handy is: you don’t have to type […]