The /tmp Lowdown
What is /tmp?
Think of your server's /tmp directory as a temporary digital workbench. It's a designated space where applications, system processes, and users can store short-lived files they need for a moment—like caches, session files, or intermediate data during a process. It's designed for data that doesn't need to survive a system reboot.
The Perils of a Packed /tmp
When this workbench gets too cluttered, it can bring your server to a grinding halt. Here are the risks:
💥 Application Crashes
Many programs depend on /tmp to function. If they can't write temporary files, they may fail to start or crash unexpectedly.
🚫 Login Issues
Even logging into the server can become impossible, as creating new user sessions often requires writing to /tmp.
🐌 System Instability
Critical system processes can be affected, leading to sluggish performance, strange errors, or even a complete system freeze.
The Cleanup Toolkit
Step 1: Identify the Culprits
Before deleting anything, you need to find out what's taking up all the space. These commands are your magnifying glass.
Check Overall Disk Usage
See a high-level overview of how full /tmp is.
Find the Biggest Offenders
List the top 20 largest files and directories inside /tmp.
Why Does /tmp Get Full?
Understanding the cause is key to prevention. Here are the usual suspects.
The Prevention Hub
Schedule Regular Reboots
The simplest solution. If your /tmp is a `tmpfs` (RAM disk), a reboot will wipe it clean. Ideal for non-critical servers.
Verify Automated Cleanup
Ensure `systemd-tmpfiles` or `tmpwatch` is enabled and configured correctly. It's the best long-term strategy.
Conduct Application Reviews
If one app is a repeat offender, check its configuration. It might be possible to change where it stores temporary files.