[mark_undoio]

Oh, and regarding how long - it depends how long it takes to fill the circular buffer of non deterministic behaviour.

Serious compute bound workloads can run days with a gigabyte of non deterministic event log. Serious IO bound workloads burn it much faster.

For a rule of thumb, think of it consuming a few MB per second, so the length of the time travel is limited by how much of that you can store.