According to documentation, "this will soft limit RAM usage - if a RAM usage goes over the high boundary, the processes of the cgroup are throttled and put under heavy reclaim pressure".

Here's my question: If I set ram-high=512.0MiB, will it mean that containers' processes will be throttled and put under heavy reclaim pressure when:

1. the total RAM usage of the system (RouterBoard / CHR) goes over 512MiB; or
2. the total RAM usage of all containers goes over 512MiB (not considering the rest of the system); or
3. the RAM usage of a single container goes over 512MiB, and only this container will experience throttling?

Thanks in advance

I'm also interested to learn what exactly is controlled by the "ram-high" parameter.

SUP-136073

I'm also interested to learn what exactly is controlled by the "ram-high" parameter.

SUP-136073

I never got a proper answer to that question, but after experimenting a bit I think the correct answer is: "ram-high" limits the total RAM usage of all containers (not considering the rest of the system).

You can experiment by changing the "ram-high" while containers are already running, there is no need to stop/start containers to apply changes made to "ram-high".

Since this is a general setting, I would assume the total of all containers.

It is the total amount containers are allowed to use before it takes action, not a per-container limit.

It also appears to result in containers restarting when the memory limit is hit. I watch the memory utilization rise and then drop repeatedly as memory gets too high and it enforces the limit.

The support confirmed:

The 'ram-high' value in the '/container/config' is set for all containers collectively.