James and I went on a tour to visit the machines we’re working with, Salomon and Anselm supercomputers. We were guided by the IT4I institute director Branislav Jansík, and it was soon apparent he is acquainted with just about every detail of the inner workings of the centre and its supercomputers.
The tour started in a meeting room, behind thick glass through which we could see the computers running. And you can believe that glass was thick, as we could only faintly hear the noise coming from the other side. As we later learned, supercomputers are so loud you will have trouble holding a conversation next to it without it looking like a game of telephone. If that’s not enough, the noise produced by all the components that are in a centre like this can be very much heard outside the actual building.
Soon after, we were led into the spacious room where the supercomputers stood. Before entering, however, we were warned that the oxygen level in the room was around 15%, compared to the normal ~21%, which can cause dizziness or even passing out. There’s a good reason for this, however – oxygen at this level prevents fire from spreading in case of an emergency. As a matter of fact, if you were to a light a candle, it would just be smothered soon after by the lack of oxygen. Fortunately, we haven’t experienced any problems and proceeded to view the components of a supercomputer.
The components of a supercomputer are neatly divided into storage, networking and processing units. Most of the racks you see the in the picture are processing units, which do the heavy lifting of high performance computing. A few others are dedicated to connecting these nodes in such a way that they can communicate efficiently, which usually involves multidimensional geometry in order to make sure no node is too far away from another topologically. And of course, there are storage nodes which hold all the data. There is actually so much data, more than a petabyte, in this case, it’s impractical to back it all up, so usually only one small portion of it is.
The computer room is far from being the only large part of a supercomputing centre, as the next stop was the infrastructure required to sustain this beast.
After leaving the computer room, we headed towards the roof and stopped at a section which deals with drawing away all the generated heat. And there is heat being generated alright! There is so much of it, they use it to keep the building warm, even during the winter, with no additional source! Moreover, only 10% of the generated heat is sufficient for this purpose.
The electricity bill is no joke, however, and if you’re interested, it’s in the order of tens of thousands of euros a month. Moving on, we went to the roof.
Arriving atop the building, we were mostly surrounded by fences around the cooling towers and chillers, and we happened to find a plant thriving without a care in the world among all the metal around it.
Anyway, this is where the tour ended, wherefrom Branislav showed us a secret shortcut door that led straight to our office, in which we could, again, tap into Salomon’s power solely through a console interface. It’s incredible to see what actually goes into the machinery that we have been using for weeks now through a very convenient and straightforward terminal on our laptops.
(Photographs courtesy of Martina Kovářová)