Rack Servers vs Blade Servers – Which is Best?
Since the dawn of mankind (or more realistically, the early 2000’s) people have debated whether blade servers or rack servers were best for their datacenter environment. It may surprise you that I personally don’t believe that blade servers fit everywhere. In fact, if you aren’t running out of power/cooling, you don’t have space constraints, you need a lot of local I/O expansion or you don’t have management issues with your physical server environment, you may be better off with rack servers. That being said, there are a lot of benefits to a blade server design as well.
Blade servers offer flexibility. From the ability to cable / power an enclosure ONE TIME to the ability to consolidate I/O connectivity, the design of a bladed server gives you the flexibility to do what you need to do in a smaller, consolidated space.
Blade servers are more efficient. Blade servers share the same space, share the same cooling, share the same power, share the same connectivity. Sharing of resources mean you utilize your power and cooling more efficiently. A blade server infrastructure gives you the ability to manage all of your data center resources in one location, helping you manage your datacenter more efficiently as well.
Blade servers offer better performance. Now I’m sure I’ll get some debate on this one. The argument is that some rack servers can hold more memory, hold more CPUs, hold more I/O and use the same chipsets as blade servers, so how can blade servers have better performance? I think blade servers (in the same chassis) can offer better performance because they share the same mid-plane. In most blade server designs, if the blade server in slot 1 needs to communicate to the blade server in slot 6, the communication never leaves the chassis. The two servers can communicate at line speed. Compared to a rack server environment, the communications would have to travel to the top of rack or edge network device before it can travel back. This may not always be the case, but it’s an advantage that only blade servers can offer.
A few weeks ago I had the pleasure of recording an Infosmack Deepdive podcast with Nigel Poulton, Bob Plankers, and Rick Vanover to discuss rack servers vs blade servers. It was a lively discussion that touches on the advantages and disadvantages of both rack servers and blade servers. We even talk about FCoTR. The podcast is now available on http://www.theregister.co.uk/ (look for the link under top stories “Infosmack podcasts”.)
Let me know what you think – your thoughts are valuable.