The sys admin's daily grind: iWatch
In a Minute
Recently, sys admin Charly was faced with the task of synchronizing a directory on a server with two NFS-mounted clients. He wanted the whole thing to happen quickly and to be easily manageable, which ruled out DRBD and GlusterFS.
My sync setup looks roughly like this: An application server cyclically reads values from a database, generates HTML files and some images, and dumps everything in the /source directory. I use NFS 4 to mount the /dest1 and /dest2 directories. When any new data arrives in /source, I want it to reach the two target directories /dest1 and /dest2.
Simple and Been Here for Years
Because complex solutions are out of the question, actually the only option left is to dump the task on inotify subsystem's plate. Inotify has been part of the kernel since 2.6.13 and provides an interface to filesystem events for userspace programs.
Apart from incron [1], I've hardly found a use for it so far, but it should be ideal for quick syncing of directories – or at least, these were my ideas on the matter. What was missing was the right tool for the task. Some quick research brought to light two candidates: lsyncd [2] and iWatch [3], but I'll focus on iWatch here.
[...]
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Digital Autonomy
• The Answer Was Already on the Shelf
• Changing the Chip Industry: How Public Investment Has Grown Open Silicon
• United Nations Open Source Portal Goes Live
• EU Open Source Strategy Plays Key Role in Tech Sovereignty Package
• France Says “Au Revoir” to Microsoft
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Dutch Government Turns to Open Source for Digital Sovereignty
Following in the footsteps of European countries, the Netherlands is looking to increase its sovereign digital infrastructure with open source software.
-
Linux May Soon Work on Snapdragon X2-Based PCs
If you're thinking about buying a Snapdragon X2-based desktop or laptop, Linux may soon be an option.
-
KDE for People Initiative Calls for AI Ban in Plasma
A new community of KDE wants the project to adopt a strict no-AI policy for KDE Plasma.
-
KDE Sets Ambitious Goals for 2026 and Beyond
KDE Connect reveals the goals for the Linux desktop darling, with one of those goals long overdue.
-
It’s Time to Test Fedora 45 Beta
Fedora 45 beta has been released with updated Gnome, KDE Plasma, and kernel.
-
Ubuntu Stonking Stingray Gets Even Rustier
Ubuntu 26.10 has completed its migration to the Rust-based coreutils.
-
AI Fixes Linux Bottlenecks Using “Hideous” Code
A Linux developer used AI to fix bottlenecks that caused problems when building the kernel. The resulting AI-generated code needed a lot of work.
-
Advanced Video Coding Still Under Patent
Brazilian patent BRPI0109962B1 has expired, which means that DivX and Xvid are no longer problematic for Linux, but it doesn’t mean that video is all of a sudden fully unleashed.
-
2,000 Vulnerabilities per Linux Release
Thanks to AI bug hunters, the Linux kernel is seeing record numbers of vulnerabilities, and it's overwhelming developers.
-
Linux Exempt from California’s Age Verification Law
So long as Linux is distributed under the GPL, MIT, BSD, and Apache licenses, the OS is exempt from being required to verify the age of its users in California.