How it works: server hardware
About servers. Everyone reading this post is making a connection to a server. In fact, you are making a connection to at least a couple. There is a server in your office or home that is allowing you to proxy onto the internet, most likely a wireless router, which connects through another server, the DSL or cable modem. There is a caching DNS resolver server on your ISP. An entire army of router servers between your home and our data center. And the last server in the chain is our web server, which actually hosts this content.
Lets narrow down the definition of a Server. We are not going to talk about IBM mainframes or Sun UltraSPARC based blade systems. Today, we care only about the servers which comprise the majority of the infrastructure of the websites you visit. These are normal computers just like you have in your house or office, with the exception of being confined into more efficient packaging. They use familiar Intel or AMD processors, normal DDR2 or faster RAM, and SATA hard drives. What really separates them from home PC’s is the software. But software is not what this blog is about.
Here is what one of our older servers looks like (below):
To compare, here is one of eBoundHost’s newest servers. This form factor is unofficially called the ‘pizza box’ due to its small dimensions.
The first thing you will notice is that the new server is not as tall. Our older hardware uses 2u (units of space) while the new servers use 1u. This allows for greater density. Some servers use as much as 7u but these are specialty machines that are filled to the brim with hard drives in gigantic RAID arrays.
Side to side comparison:
These servers fit into specialty (read expensive) racks that have 42u of storage in each rack. This means that when filled with 2u servers, we can only install 21 machines instead of 42 1u servers. It’s a dramatic difference when you talk about a server room full of racks such as in our facility:
Of course the entire 42 units are not available for servers, there are switches, power distribution units, firewalls, intrusion detection equipment. All considered, we are happy to have 30 servers in one rack.
There is also the consideration of electricity and heat. A rack full of servers eats electricity like a hungry SUV, and produces just as much heat pollution. 30 servers stacked on top of each other, blowing air into the same direction, require an amazing amount of cooling, which needs big air conditioners that move a lot of tonnes of air. That’s all I’m going to say about that. Data center challenges is going to be saved for another blog entry.
To jump back into server hardware. Here is the same 1u server without its cover.
Motherboard, CPU, heatsink, RAM, hard drive and a very powerful cooling fan. Seems simple enough. Another picture:
Every server is custom built. When an older machine comes off line, we generally sell it through eBay and build a new server to take its place. The nature of hardware is such that components wear out and fail eventually. Our clients and our reputation are far too important, so we give old hardware the boot and use all new equipment.
Here are some servers in action. The following pictures may not be completely safe for geeks, they may cause weakening of the knees and a desire to run out and fix something. Please refrain, it will pass:
These (above) are dedicated servers. Inventory tags have been obfuscated in order to protect the innocent.
(below) Are some specialty machines which have 15k SAS (fast/expensive) hot swappable hard drives in RAID array. Used for our shared servers, VPS machines, and some powerful dedicated servers.
Each server is built by our staff. We love them so much that we have hundreds of them 😉
More to follow, there is so much to cover: data center, operating systems, server software.
Artur
April 6, 2008 