The datacenter is in San Diego - a quick Google confirms that external humidity pretty much never drops below 50% there.
replyThings would be different in a colder climate where humidity goes --> 0% in the winter
Low is good if you are also adding more humidity back in. If you want to maintain 45-50% (guessing), then you would want <45% environmental humidity so that you can raise it to the level you want. You're right about avoiding static, but you'd still want to try to keep it somewhat consistent.
replyIt is much cheaper to use external air for cooling if you can.
Yeah but the article makes it sound as if lower is better, which it is definitely not. And yeah you need to control humidity, that might mean sometimes lowering, and sometimes increase it by whatever solution you have.
replyAlso this is where cutting corner indeed results in lower cost, which was the reason for the OP to begin with. It just means you won't get as good a datacenter as people who are actually tuning this whole day and have decades of experience.
Low humidity causes static electricity.
replyRAM that is plugged in and operating isn't subject to external ESD, unless you count lightning strikes. Where are you getting this?