Reduce Memory Cache Script for Linux

Overview

This project provides a small Linux automation that can drop filesystem caches when available memory is below a configured threshold.

It includes:

• reduce_memory.sh: Script that checks memory and optionally runs cache drop.
• reduce_memory.service: systemd oneshot service that executes the script.
• reduce_memory.timer: systemd timer that triggers the service every 10 minutes.
• reduce_memory.logrotate: logrotate rule for /var/log/reduce_memory.log.
• setup.sh: installer/uninstaller for all components.

Behavior

The script prefers MemAvailable from /proc/meminfo to decide whether to drop cache. If MemAvailable is not present, it falls back to MemFree.

Default threshold:

• MEM_MIN = 512 MB

Configuration source precedence:

1. First argument passed to reduce_memory.sh
2. MEM_MIN_ENV from /etc/default/reduce_memory
3. Built-in default (512)

Installation

Clone the repository:

git clone https://github.com/byfranke/reducememory
cd reducememory

Make installer executable and run as root:

chmod +x setup.sh
sudo ./setup.sh

The installer:

• Copies files to /usr/local/bin and /etc/systemd/system
• Installs /etc/logrotate.d/reduce_memory
• Writes /etc/default/reduce_memory
• Enables and starts reduce_memory.timer

Custom Installation

When setup.sh asks the installation type, select Custom and define the threshold in MB. The selected value is written to /etc/default/reduce_memory as MEM_MIN_ENV.

Uninstall

Run:

sudo ./setup.sh uninstall

This disables/stops the timer and removes installed script, systemd units, logrotate config, and environment file.

Operational Notes

Linux usually manages cache efficiently, so dropping caches frequently can hurt performance. Use this automation only when you have measured memory pressure and validated the impact on your workload.