From what we learned last September with the spike in Mastodon usage, we're getting a head of things. We're setting up multiple Lemmy servers to help balance load on front end requests just as we do with Mastodon. So far, Lemmy's performance has been excellent with minimal resource usage, but distributing the load for pict-rs and front end requests should help us if we do indeed (and hopefully so) get a rush of new folks that want to leave reddit and grow the Fediverse.
Think of the cats. Join lemmy.sdf.org is a pretty good slogan.