Looking for application monitoring and observability solutions? On this page, I’ve listed the top application performance monitoring (APM), infrastructure monitoring, and observability solutions to date. The listings are updated periodically as APM and observability solutions continue a rapid evolution. While I haven’t tested all of these solutions, I’ve used more than a third of them. […]
“MySQL server has gone away” error – Solution(s)
The MySQL server has gone away error, which means that the MySQL server (mysqld) timed out and closed the connection. By default, MySQL will close connections after eight hours (28800 seconds) if nothing happens. However, in some cases, your web host, DBA, or app developer may have decreased this timeout setting, as discussed below. MySQL […]
How to Enable Unattended Upgrades on Ubuntu/Debian
Linux server security is of critical importance to sysadmins. One central part of keeping Linux servers secure is by installing security updates promptly. Too often, there are compromised servers on the internet due to pending security updates waiting for a manual update. On both Ubuntu and Debian, the unattended-upgrades package can be configured to perform […]
Quick Tip for a more stable Arch Linux experience
Disclaimer: Everything below has been published previously online in Arch’s extensive wiki. However, for whatever reason there’s still a lot of misinformation about Arch’s stability and many users are not aware that these published tips exist. This short article aims to raise awareness of the best routes for a more stable Arch Linux experience. That’s not […]
What CentOS alternative distro should you choose?
In January 2014, CentOS announced it was officially joining Red Hat while staying independent from Red Hat Enterprise Linux (RHEL) under a new CentOS governing board. However, in December 2020, Red Hat requisitioned that CentOS terminate the development of CentOS 8. They also announced that support would be shifting to a CentOS alternative rolling-release Linux […]
Linux: ncdu and mc to manage large directories
Creating, modifying, and deleting files are everyday tasks performed in any operating system, even more so by Sysadmins, Developers, and Programmers. For the most part, these tasks are fast enough when managing a handful of files. However, on Linux and especially with servers, you may at some time have to manage millions or even billions […]
bash: /usr/bin/rm: Argument list too long – Solution
Over time, the storage used on Linux systems you manage will grow. As a result, you will, at some point, try to delete, move, search, or otherwise manipulate thousands of files using commands such as rm, cp, ls, mv, and so on, which are all subject to this limitation. As such, you will eventually come […]
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 […]
What is iowait and how does it affect Linux performance?
I/O wait or iowait, wait, wa, %iowait, or wait% is often displayed by command-line Linux system monitoring tools such as top, sar, atop, and others. On its own, it’s one of many performance stats that provide us insight into Linux system performance. I/O wait came up in a recent discussion with a new client. During our […]
Free vs. Available Memory in Linux
At times we will need to know precisely how our Linux systems use memory. This article will examine how to use the free command-line utility to view memory usage on a Linux system. In doing so, we will clearly define the difference between free vs. available memory on Linux systems. Free vs. Available memory […]