A lot of times I see discussions about whether or not homelabbers should use rackmount servers or tower servers. I’m going to share my reasons for preferring rackmount gear.
No, I don’t mean scaling out a web application or anything like that. I mean physical space. You can pack a lot of power into 42U. Heck, even 12U can hold enough. With the tower form factor, you can’t easily scale up. Stacking 3 or 4 towers on top of each other is unstable (and very unsafe!). Remember building blocks as a kid?
With rack mount servers, they have a large surface area. You can stack 9 2U servers on top of each other and they’re solid as a rock. I would not even attempt to stack 9 towers on top of each other.
Need another reason? Look at major cities for inspiration. One World Trade Center has 3.5 million square feet in a 200 foot square. My local Amazon Fulfillment Center is just over 1 million square feet with dimensions ~1796 feet x ~568 feet.
Simply put: I can cram in more compute in less space.
It’s all standard
Good old AT&T brought us the 19 inch rack as we know it today, all the way back in 1922. Let’s ignore the Western Electric 23-inch standard as it isn’t that common. They defined a rack unit as 1.75 inches which is the height of 1U. So a 2U server is 3.5 inches. That means no matter what brand, a rack mount server is always going to be the same width which makes them stackable, even outside of a rack.
Towers have no standard. Yes, the motherboard inside has a standard, but the actual case does not. You can have a Micro-ATX motherboard inside a huge case. And a lot of cases will be extra tall to fit things like lots of drives. Put two ATX cases side by side. I bet they won’t match up unless they’re the same make and model.
Rack servers have better managed airflow. That means the front is intake, the back is exhaust. With my server rack, I can easily channel all that hot air and vent it elsewhere. With a large stack of towers, that’s not happening unless they were all in a single room.