> * why do the racks have wheels at all? Doesn't seem like a standard build, and turns out the be risky They probably aren't "standard" in any kind of common s

> * why do the racks have wheels at all? Doesn't seem like a standard build, and turns out the be risky They probably aren't "standard" in any kind of common sense. Google and the other big tech firms design their own hardware and likely have it assembled remotely and delivered as a complete rack. Wheels make positioning it easier. It's also not uncommon to need to move racks of machines around (say, during a cluster refit or to change capacity in different DC halls). Not having wheels is likely more of a pain than the potential gains of omitting them. > * there should be at least daily checks on the data center, including a visual inspection of cooling systems and the likes. I don't know if daily visual inspection of racks is also a thing, but should find that pretty quickly. Google has millions of machines and dozens of datacenters. Its techs are likely already 100% busy replacing HDDs and other routine stuff. Noticing a single rack failing (within error budget) isn't going to be a priority so it's unlikely someone is employed to do that. Cooling/power systems are definitely monitored on a more macro level. > * monitoring temperatures in a data center is pretty essential, though I must admit I don't know enough if rack-level temperature monitoring would have caused overheating of CPUs in the rack. There's likely DC-level temperature monitoring. Again, systems are designed to cope with some amount of failure so it's not important to monitor everything and alert someone every time anything changes. When dealing with millions of things you need to look at aggregations.