Memory: dynamic mode

Dynamic memory gives an instance a Minimum and a Maximum. It starts with the maximum, and MSL keeps watching how much Linux actually needs, handing back what it isn't using and letting it have more again as it needs it — never above the maximum, never below the minimum.

Choosing the numbers#

• Maximum is what your Mac sets aside when the instance starts, and the most it can ever have.
• Minimum is as far down as MSL will ever squeeze it.

The same warnings as manual mode apply to the maximum, and the minimum can't be larger than the maximum.

How MSL decides#

Rather than guessing from one number, MSL looks at how much memory Linux is really using, how much it could free if it had to, and — most tellingly — whether programs inside are stalling while they wait for memory. It gives memory back gently when there's plenty spare, and returns it quickly the moment Linux starts to struggle. Linux images don't use swap, so MSL never squeezes an instance below what its programs are actually holding.

The live readout#

While a dynamic instance is running, the bottom of the card updates every few seconds:

If the guest has swap turned on, a note says so: MSL still sizes it conservatively, but swap changes what running out of memory feels like.

When it takes effect#

Switching between Manual and Dynamic, or changing the numbers, applies at the next start — like every memory change.