If you're planning a big ad campaign, or just got an unexpected traffic surge, then Autoscaling is a simple solution to temporarily increase resources with a few clicks. Go to Addons and click Manage Autoscaling.
Do not update the WP core, plugins, theme, or upload, delete, or change files while Autoscaling is running. In short: only process orders and manage customers while you're running Autoscaling.
You can choose how long you want to run it (from 12 hours up to 3 days) and the multiplier of the current resources. At the bottom, you see the minimum and maximum charges for the selected time. Autoscaling gets automatically disabled after the time runs out or you can disable it manually at any time.
Autoscaling requires a server restart, so the store will be down for a minute to get the new configuration.
You can see the increased resources on the Server Metrics if they were required: