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 […]
What is iowait and how does it affect Linux performance?
iowait (wait, wa, %iowait, wait%, or I/O 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 support […]
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, ls, mv, cp, and so on, which are all subject to this limitation. As such, you will eventually come across […]
Linux server needs a RAM upgrade? Check with top, free, vmstat, sar
Sometimes, it can be a bit of a challenge knowing if and when you should upgrade the RAM (random access memory) on your Linux server. Even more so, when deciding how much memory you should add, or if you have adequate memory, how do you make the best use of it? This article will walk […]
Are you measuring Linux web server memory usage correctly?
This article was first published in 2014. After which, there was a welcomed change to the Linux kernel in 2016, as mentioned in the 2017 article: Does your Linux server need a RAM upgrade? Let’s check with free, top, vmstat and sar. As a server administrator or web developer, it’s your responsibility to stay informed about […]
Linux Performance: Almost Always Add Swap Space – Part 2: ZRAM
In the previous article, we looked at how swap space, particularly swapping, can severely slow down Linux performance. We then tweaked Linux kernel parameters to better use server memory and 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 […]
Linux Performance: 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 be better to delete swap space? The answer is: No. There are performance benefits when swap space is enabled, even when you have more than […]
btop – the htop alternative
Have you ever experienced slow application performance on a server and wondered which process was causing the bottleneck? In a production server environment, monitoring system performance and hardware resource usage in real-time is crucial. That’s where system monitoring tools come in handy. And, with the availability of numerous command-line system monitoring tools, you’re spoiled for […]
“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 […]
Fix Error: Failed to download metadata for repo ‘appstream’ – CentOS 8
As we all know, CentOS 8 reached its End of Life (EOL) on December 31, 2021, and CentOS Linux 7 will reach its end of life (EOL) on June 30, 2024, marking a significant shift in the CentOS ecosystem. This transition to CentOS Stream leaves system administrators and users with some important decisions to make. […]