Running several instances at once

How Settings Saver keeps its store consistent when several Minecraft instances run at the same time, and whose change wins when two of them sync.

You can run several instances with Settings Saver at the same time, on the same or different Minecraft versions and loaders. They share one store without corrupting it or undoing each other's changes.

Locking and safe writes#

Every time an instance reads, changes and writes the store (Save, Load, auto sync, profile changes), it holds a lock: one inside the game and one on the .lock file in the store, which other running games respect. Files are written to a temporary file first and then moved into place in one step, so a crash or a closed game never leaves a half-written file behind.

Whose change wins#

In the Auto modes each instance saves only the settings you changed in it since it last synced, never its whole file. So with two instances on Auto:

• You change FOV in instance A and render distance in instance B. The profile gets both.
• You change FOV in A, then FOV in B. The profile has B's value, the last change.

Pressing Save in an instance writes every setting of that instance that differs from the profile, so a Save can replace a change another instance synced earlier.

Seeing another instance's changes#

A running instance doesn't reload the profile when another instance changes it. It picks up the changes:

• when you press Load settings from profile, or
• at its next launch, in the Auto + always apply sync mode.

Instances on different profiles#

Each instance syncs only with its own profile, so a pvp instance and a default instance never touch each other's settings. When you switch an instance to another profile, it starts saving its later changes into the new profile.