I had a chance to see the GeoCities Exodus 1 cage in 2000 when I was at eBay Payments.
It used LaCie JBOD stacked to the ceiling as storage devices, and a 3′ diameter floor fan to move the hot air to other customers’ cages. 
$50 Floor Fan Protecting $millions in GeoCities equipment from outside their colo cage. What could go wrong?
Their cage left an impression on me, and demonstrated how:
- ghetto colo can work
- cages can achieve very high densities
- devices can work at very high temperatures for extended time intervals
- to work your colo provider (there’s no way they got prior approval for that floor fan!)
Below is some photos of one of their cages with Sun and Netapp gear:
The GeoCities Cage at Exodus Communications [1999] HN Comments
Note their use of Veritas Volume Manager.
Until around 1998, linux did not have a journalled filesystem. I started evaluating Reiserfs 3 on Suse Linux at that time on my personal machine. A Suse salesrep a decade later refused to believe that anybody in the USA could have been using Suse back then.
The other cage from 2000 that left an impression on me was About.com’s, which had a Sun E10k server ($2 million each fully populated). I don’t think they ever launched a product, yet they had the same equipment as eBay’s main cage.
I was talking to some other sysadmins with gear at Exodus 3 and 4, and they mentioned a lot of customers also built out their colo but never launched.
Dedicated Internet Access & Hosting Agreement between Exodus and GeoCities
W: Exodus Communications