[ivirshup]

I think there are backup systems. I sometimes walk by the Cloudflare SF offices on weekends and it looks like the lava lamps are off.

[eastdakota]

They should never all be off at the same time. We do cycle through each of them turning off for a period of the day. But, even if they were all off, there are lots of other sources of entropy we use, most of which are for more traditional if far less visually interesting.