They went through a spectacular system-wide crash a few years ago with Jeffree Starr cosmetics - similar circumstances (despite knowing it was coming, the sale took down storefront and admin for merchants across the platform) and probably learned a few things from that experience. There's some interesting* behind-the-scenes footage on YouTube from that crash:
https://www.youtube.com/watch?v=OTCOoVApM_U&t=1811s*arguable, but I think it's interesting if you've ever been involved in a high stakes ecommerce launch