How does vm.overcommit_memory=1 impact Unraid?
Changing this setting on your Unraid host is generally safe and actually recommended if you run memory-intensive Docker containers (like Redis or MongoDB).
- What it does: It tells the Linux kernel to “trust” applications when they ask for memory, rather than checking if it has enough physical RAM + Swap to back every single request immediately.
- The Positive: It prevents Redis from crashing during a “background save” (snapshot). Redis uses “copy-on-write” to save data; without overcommit, the kernel might refuse the save because it thinks Redis is trying to double its memory usage.
- The Risk: In an extreme “out of memory” (OOM) scenario, the kernel is more likely to trigger the OOM Killer to force-kill a process to save the system.
- Recommendation for Unraid: Most Unraid users running Redis/Plex/Home Automation set this to
1. It won’t destabilize Unraid itself unless you are already red-lining your RAM (e.g., 31GB used out of 32GB).
To apply it permanently on Unraid:
Go to the Unraid WebUI -> Terminal and run:
bash
sysctl vm.overcommit_memory=1
Use code with caution.
To make it stick after a reboot, add that line to your /boot/config/go script.