Performance Archives - Igor Oseledko https://www.igoroseledko.com/category/sysadmin/monitoring/performance/ I know everything. Just not all at once... Fri, 21 Nov 2025 01:48:02 +0000 en-US hourly 1 Analyzing atop Logs with atopsar https://www.igoroseledko.com/analyzing-atop-logs-with-atopsar/ Fri, 21 Nov 2025 01:48:02 +0000 https://www.igoroseledko.com/?p=133415 Originally published November 22, 2019 @ 5:38 pmI have discussed atop previously but concentrated primarily on how to run it and how to collect data. Now I’d like to spend some time talking about ways to analyze the data collected with atop. Included with the atop package is atopsar – a utility design to extract […]

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]]> Server and Application Resiliency Testing https://www.igoroseledko.com/server-and-application-resiliency-testing/ Mon, 08 Sep 2025 22:01:08 +0000 https://www.igoroseledko.com/?p=134738 Originally published September 9, 2022 @ 1:15 pmYou are deploying a new application cluster and wonder how it will perform under less-than-ideal conditions: heavy system load, slow storage, network performance degradation. Application resiliency testing is integral to any application architecture but is often passed over because the process is considered overly complex and time-consuming. Here […]

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]]> Analyzing Network Performance https://www.igoroseledko.com/analyzing-network-performance/ Sun, 17 Aug 2025 01:46:05 +0000 https://www.igoroseledko.com/?p=133240 Originally published August 18, 2019 @ 7:09 pmMuch of network performance analysis will be comparative in nature. Thus, seeing the output of multiple commands side by side can be quite useful. Bash has a useful little utility called pr and we’ll make use of it. Side-by-side traceroutes Step 1: create hostlist.txt and populate it with […]

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]]> Working with ffmpeg on Multi-Core Systems https://www.igoroseledko.com/working-with-ffmpeg-on-multi-core-systems/ Fri, 01 Aug 2025 02:33:39 +0000 https://www.igoroseledko.com/?p=133194 Originally published August 1, 2019 @ 9:25 pmWhile ffmpeg has multithreading capability, getting the best performance on multi-core systems calls for something more than just playing with the -threads option. I’ve seen suggestions to set the -threads option to 1.5 the number of cores, which doesn’t make any sense. The most common choice for this […]

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]]> Measure DNS Server Performance https://www.igoroseledko.com/measure-dns-server-performance/ Thu, 09 Jan 2025 15:57:51 +0000 https://www.igoroseledko.com/?p=133021 Originally published January 10, 2019 @ 6:35 pmThis is not an entirely proper way to benchmark a DNS server, but, in a pinch, it should give you some idea of its responsiveness and stability. The commands below require dig (provided by the bind-utils package), and shuf (provided by the coreutils package). Pretty standard stuff you […]

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]]> QNAP NAS Performance Analysis https://www.igoroseledko.com/qnap-nas-performance-analysis/ Wed, 06 Nov 2024 23:47:34 +0000 https://www.igoroseledko.com/?p=134641 Originally published November 7, 2021 @ 4:54 pmThe QNAP Resource Monitor utility available via the Web UI provides a lot of useful functionality with good visual presentation. However, sometimes you need just a little bit more detail to help track down a particularly elusive performance issue. The purpose of this quick write-up is to help […]

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]]> NFS I/O Stats with Logging https://www.igoroseledko.com/nfs-i-o-stats-with-logging/ Fri, 23 Aug 2024 14:50:50 +0000 https://www.igoroseledko.com/?p=134491 Originally published August 24, 2021 @ 6:58 amThe nfsiostat is an excellent tool for analyzing NFS performance. The only major problem with this utility is that it’s designed to be used interactively. It does not have logging or timestamping capabilities. I needed to get information about NFS mount performance during a nightly backup, and I […]

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]]> Atop Script with Scheduling and Logging https://www.igoroseledko.com/atop-script-with-scheduling-and-logging/ Tue, 02 Jan 2024 20:49:17 +0000 http://www.igoroseledko.com/?p=131719 Originally published January 2, 2018 @ 10:18 amWhen something is going down on a server, the first thing most sysadmins will run is the venerable top utility. This happens automatically: if you suspect the server is being sluggish, your fingers just type top without you even thinking about it. Unfortunately, top and many similar tools will only show you […]

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]]> Linux CLI Network Speed Test https://www.igoroseledko.com/linux-cli-network-speed-test/ Thu, 28 Sep 2023 03:01:36 +0000 https://www.igoroseledko.com/?p=133254 Originally published September 1, 2015 @ 6:52 pmThe speedtest.net is probably one of the more popular bandwidth testing utilities, Unfortunately, this and many other similar tools require a Web browser with late-version Flash or Java support, which can be problematic on Unix servers. Fortunately, speedtest.net also provides a Python-based Linux CLI utility that’s easy to […]

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]]> Understanding Memory Utilization in Linux https://www.igoroseledko.com/understanding-memory-utilization-in-linux/ Fri, 01 Sep 2023 20:11:48 +0000 https://www.igoroseledko.com/?p=133953 Originally published August 26, 2020 @ 12:25 pmThis is a depressing – and all-too-common – scenario: a user runs the free command and opens a support case because he sees zero “free” memory on the server. For years I’ve been trying to explain to users – developers, application engineers – how memory allocation works in […]

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