Image via Google Maps: g.co/maps/br472
Estimated server count: 417,600
The building lower right is the "original" of Google's container-based data centers. It opened in 2005 and is featured in the video tour released by Google in 2009. In fact, this is the only building where we know the exact layout of the server containers within the building. This is because the video shows a floor plan which can be matched up with the satellite image. The video says this building contains 45 containers - one row of 15 one-storey, another row of 15 two-storey stacks. I've gone out on a limb, however, and assumed that the single-storey has since been double stacked. Why go for single stacking when you can have double? Unless the building construction somehow precludes it. I've also guessed that the remainder of that building doesn't house any container-based servers. This is because, unlike all Google's other data warehouses, no external cooling systems can be seen. Perhaps this area houses systems that pre-date the container-based system, or is used for other functions.
The larger building upper left is surrounded by cooling systems which are typical of almost all of Google's other data centers. It is likely that this building houses exclusively container-based servers. The containers are probably packed in as densely as possible. I have conservatively estimated 6 x 25 rows of containers. It's possible there are 8 x 25 rows, which would mean 464,000 servers in this building instead of 348,000. The buildings upper right don't appear to be owned by Google.
Return: All Google data centers
Google's own page about this data center: google.com/datacenters/douglas-county