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kumo.set_memory_soft_limit(LIMIT)

Since: Version 2025.03.19-1d3f1f67

The functionality described in this section requires version 2025.03.19-1d3f1f67 of KumoMTA, or a more recent version.

Set the soft limit for memory utilization. This usually defaults to 75% of amount of physical RAM in the system, but ulimit or cgroup constraints may modify the value.

When the system is using more than the soft limit, incoming traffic will be turned away and various other memory reduction measures will be enabled until the memory usage falls below the soft limit.

You might want to modify this value if you have a lot of RAM and want to use more than 75% of it in the common case.

See Memory Management for a discussion on how kumomta manages memory usage.

It is recommend to set this during the pre_init event.

The LIMIT is expressed as an integer number of bytes.

kumo.on('pre_init', function()
  kumo.set_memory_soft_limit(1024 * 1024 * 1024)
end)