> One box can’t be distributed across multiple racks in the data center to guard against downtime if a switch crashes. Never mind that—one box can’t be deployed

> One box can’t be distributed across multiple racks in the data center to guard against downtime if a switch crashes. Never mind that—one box can’t be deployed across multiple data centers. If you deploy to multiple DCs you can fail over if one DC starts having issues. Wouldn't you just have multiple NICs on one box for redundancy there? With any backups being sent a database write-log for replication? > n any case, payments aren’t CPU intensive but it’s a prime case of hurry-up-and-wait. Lots of network IO, so while you won’t saturate the CPU with millions of transactions on the same box, I could easily imagine saturating a NIC. If you're vertically scaling, wouldn't you just have the main database server host the database files locally, using fast NVMe SSDs (or Optame), in the box itself, instead of going over the network? Enterprise NVMe drives can perform 500,000-2,000,000 IOPs, with about 60us latency. And Optane is about 4x faster. Why would a database server need to saturate network bandwidth? Anyways, I'd love to see the actual SQL query for one of their transactions...