Here’s something I wrote before:
Particularly
As-shipped, the kernel will reject allocations which it can’t satisfy. With this tweak, it will accept those allocations, and failure might be averted, or it might happen later when the allocation becomes usage.
If your total of RAM and swap is big enough, you’ll never need to change this setting. If your total is not big, changing it might help.
Also
It’s to increase the amount of virtual memory available. (That is, the sum of RAM and swap.) If you run out of RAM, you start to suffer performance problems. But if you run out of virtual memory, processes will fail to start or will die or be killed. It gets brutal.
Those of us with both small RAM and small disk may not be free to add loads of swap, but 2G seems to be a good minimum. (If you had 16G of RAM you might not need any swap, but that’s another story. It’s the sum of the two which matters, when the problem is things failing.)
As for the resistance, I think it’s because of a perception that this change is for the benefit of redis, and most people won’t need it.
Edit: this recent thread is possibly a case in point, where a smallish instance ran out of memory, and didn’t have overcommit set. But we don’t know if setting overcommit would have solved this problem - the person upgraded to 8G RAM.