A chassis is a pretty big deal around here but not the kind that keeps the body, suspension and wheels of your car all attached together. In our world, a chassis is the enclosure that handles all the non-computing tasks required to support multiple servers, including providing power, cooling, connectivity and manageability to each blade server that it’s holding.
“Blades” are redundant self-contained servers that fit into a chassis with other blades. Each chassis holds 8 to 16 blades – so that’s 16 to 32 processors and up to 96 cores per blade. Each blade supports up to 48GB of RAM or up to 768GB per chassis.
Our latest data center upgrade involves multiple redundant chassis. Here is a typical HP Blade Chassis – this one with 16 blades:
Blades are pretty cool servers. Their major selling point is that they afford nearly 100% uptime. They can tackle any task you’d like them to:
- Database and application hosting
- Virtual server hosting platforms
- File sharing
- Remote desktops and workstations
- Web page serving and caching
- Streaming audio and video content and more.
If your system needs more power, you just add another blade server to your chassis. They provide reliability through resilience and quality.
Servers can fail, we all know that. But when using VMWare, you can cluster 8 – 16 servers together in a single chassis. By doing this, when a server fails, it’s has almost negligible impact because the workload moves from all 8 for example to 7. None of the servers are running at full capacity so if one fails, it’s no problem.
The chassis itself has a high degree of resiliency to it. It has 4 power supplies (rather than the usual two of a stand-alone server). These power supplies are basically mini-transformers with their own fans. If one fails, as they sometimes do, it can be replaced within 24 hours without impact. And that’s a good thing.
All disk arrays – (storage systems linking multiple hard drives into one large drive) have at least 2 power supplies but could run off of one. Having two power supplies provides protection from 2 kinds of problems:
1) If the power supply stops working, another one takes over and handles the power for both
2) By having separate power paths, one side of device is directed into one path, the other in another separate path. If your data center is designed correctly, you are plugging into distinctly different power feeds. So if your electric company has a power failure, or a transformer blows up, or a major wire gets cut, the data center will stay lit. Even if one side of the power in the data center goes down, the power to your servers stay on and you don’t even go to diesel. However some data centers (not ours) do not have 2 power station feeds. You would have multiple concurrent power paths into your space.