NCDU-fu

Published by Anonymous (not verified) on Thu, 19/10/2017 - 8:55pm in

Tags 

sysadmin

Sometimes it feels good to have some meager sysadmin competencies, such as knowing how to quickly identity where large files are in a particular hosting account. This issue comes up from time-to-time when someone discovers all their storage space has been eaten up, but they are not sure where and why.  Often this is a symptom of a larger problem, such as an error_log run out of control which suggests bad process for a particular application, etc. That was the case on a ticket this morning, and luckily I knew the NCDU command. What is NCDU, you ask?

Ncdu is a disk usage analyzer with an ncurses interface. It is designed to find space hogs on a remote server where you don’t have an entire graphical setup available, but it is a useful tool even on regular desktop systems. Ncdu aims to be fast, simple and easy to use, and should be able to run in any minimal POSIX-like environment with ncurses installed.

In other words, a script for a remote server that finds big files. You can install it on your server, and then run it by navigating in command line to the offending account, which on our cPanel servers would live at /home/offendingaccount and running the command NCDU. After that, it will list all the directories and their sizes, followed by files.  You can then locate the directory with the largest file usage, and then change to that directory and run NCDU again until you find the offending file. In the example this morning, it was a 6 GB error_log in a directory running WordPress, easy fix to clean out space, and a good heads up things in that account need to be checked for a bad plugins, theme, etc.

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