As you can see from our handy sidebar widget, Data Centric is The Planet Blog’s reining “Most Popular Post.” While one could make the argument that visitors are all tuning in to read content written by a person many believe to be one of the most brilliant authors of his generation, let’s be honest … Everyone just wants to look at the pictures.

Given the title of this post, you can see that I’m not reinventing the wheel for my 100th official blog post. I convinced Todd to lug his fancy DSLR camera up to H2 for another data center tour a few months ago, and we’ve got a fresh photo tour of the facility for you. In some cases, you’ll notice that the DC looks a bit different than it did almost exactly three years ago — especially in Phase 3.

Since you’re already thinking of Phase 3, why don’t we start there? You probably don’t recognize this row of servers. The last time we posted a picture of this area in the data center, it was an expanse of floor tiles.

As you can see, we’re still obsessive about cable organization. Each color cable carries a different kind of traffic, and each individual cable is labeled on both ends. The yellow plastic conduit carries fiber between the transport cage – where the Internet “drops” into the data center – and the DC’s customer access routers.

In less colorful – but equally important – parts of our facility, the data center’s power rooms, generators and battery backup room are still awe-inspiring.

As we head back into Phase 3 to look at a “cold aisle” of rack-mount servers, it’s worth observing that you’re not greeted with the wave of 68-70 degree air you might have experienced a few years ago. We’ve improved our cold air distribution in the data center and increased the ambient temperature to keep the servers operating efficiently. The current ASHRAE standard temperature for a DC is now around 80 degrees. To allow for a little fluctuation up and down, we keep our facilities around 75 or 76 degrees. In the above picture, you can see the perforated tiles that allow the cold air from under the floor to enter the data center.

Swinging around the back of a rack-mount server rack, we get to admire more artistic cabling. As I mentioned, we label and run cables precisely from end to end. This precision looks fantastic, and it’s also entirely functional … If we had spools of slack on each side of the cables, it would be much more difficult to access cables and replace them if necessary.

Before you start thinking we’ve abandoned the tower server racks you saw three years ago, we’ll head back into Phase 1. In the first Data Centric post, I didn’t snap any pictures of a cold aisle between tower racks in H2, so I want to make sure I don’t omit that again. One of the first questions you might ask after seeing this picture is, “Why aren’t the servers aligned?” The answer is pretty straightforward: Because the size of a tower chassis can vary significantly, we have to choose whether to line up the front or the back. When our DC operations team works on servers, they generally access them from the hot aisle, so that’s where they are all aligned.

Does this picture look familiar? It should … it was taken from the exact same spot as this one. As you can see, the backs of all of the tower servers line up beautifully, and Todd’s camerawork is much better than mine was. If you’re looking for differences between the two, you’ll probably wonder why you can’t see the aisle on the other side of the CRAC unit in the new picture. That’s quite a keen eye you have there.

You can’t see the other row in the new picture because we’ve installed chimneys on all of our CRAC units. As you remember from physics class, warm air rises, so if we want to cool the facility most efficiently, we should pull the warmest air from the room. In the picture from three years ago, the air conditioning unit would pull colder air from lower in the room.

The white cabinets you see at the ends of the aisles here are power distribution units (PDUs). Power is sent from the power room into the data center under the raised floor. Each one of the PDUs in turn makes that power available to servers in its data center row.

If our data center operations team is responding to a ticket to help a customer from the floor, they’ll wheel around one of these bad boys to access the customer’s server directly. Three years ago, you might have seen a *gasp* CRT monitor.

I don’t have anything to say about this picture. It’s just a great shot of a row of rack-mount servers.

All good things must come to an end, so to close out the blog, we can walk you out of the data center just as we would if you came for an in-person tour. To the left, the data center operations team is keeping an eye on tickets, orders and DC stats.

If the dozen pictures we’ve included here don’t sate your appetite for data center goodness, head over to our Flickr photostream for more.

Did we miss anything? Is there anything else you want to see? Leave a comment below or let us know on Twitter or Facebook!

-Kevin