On wednesday a vendor came in to give their marketing pitch on why we should be running blade servers. My personal opinion is that blade servers are a waste of time and money. Why do I say they are a waste, well here are my points:
- Power Requirements: Said vendor requires 4 x 2000watt power supplies to support 14 blades. (8000 Watts) They say that they are getting ready to up them to 3000 watt power supplies, so now we are up to 12,000 watts for 14 servers.
- No hot swap drives: If you want hot swap drives you have to buy a hot swap drive blade, so if you wanted every blade to have hot swapable drives, you in turn only get 7 blades in the box instead of 14. Effectively giving you 7 1U servers now.
- Shared backplane: Granted they have 2 backplanes in the chassis, but the problem is that they are both tied to the same support, and to replace either you have to shut down all the blades in the box. Not a very good idea if you have to shut down 14 servers to fix one little problem.
One of the biggest problems I have with blade centers is the power and heat they throw off. For example the vendor said that they could put 6 of their blade centers in a 42 U rack. So we take 6 x 12,000 watts, and you get 72,000 watts of power in 1 rack, in comparison the SunFire E25K we have running is using about 26,423 watts total of power right now. Or you could take 42 of the SunFire X2100 servers and they would only use about 12,600 watts.
Now if we look at the BTU’s generated by each:
If we assume the following: 1 watthour = 3.412 Btu
We see the following:
1 Rack with 6 Blade Centers uses 72,000 Watts or 245,664 BTU’s
1 Rack with 42 X2100 Servers uses 12,600 Watts or 42,991 BTU’s
1 E25K 26,423 Watts or 89,838 BTU’s
Now to find out Ton’s of AC required:
1 ton = 12,000 BTU
1 Rack with 6 Blade Centers: 20.47 Ton
1 Rack with 42 X2100: 3.58 Ton
1 E25K: 7.48 Ton
Now the “average” Data Center AC unit has around 30 to 40 Ton capacity depending on whether you used compressorized system (10 to 30 tons) or a chilled water system (10 to 65 Ton).
So what does that mean? You almost need 1 AC unit for each full rack of Blade Centers.
When you factor all this together, are blade centers really saving you anything. Not in my opinion.
The other “selling” point they try to tell you is better is that you don’t have to run as many cables to your rack. This may be true, but now instead of maybe one large enterprise switch you have to manage, you now have 12 switches that need to be connected back to one or two central switches. Same with the SAN.
So lets see how many cables there really are (if the systems were configured to be redundent where possible):
| System |
Power Cables |
Network |
San |
Total cables |
| 1 Blade Chassis |
4 |
at least 2 |
at least 2 |
8 |
| 6 Blade Chassis’ |
24 |
at least 12 |
at least 12 |
48 |
| 1 X2100 |
1 |
2 |
2 |
5 |
| 42 X2100 |
42 |
84 |
84 |
210 |
So yes, you will reduce the number of cables running to a rack, but that is about it for the cable “benefit”.
Now what is the real use of blade servers? Is it to “virtualize” your environment? Don’t think so. Is it to reduce the footprint of what the servers use? Maybe. But in the end, you still have X numbers of servers to manage. If you were to use the 14 blades per chassis and had 6 chassis per rack, that is 84 individual servers to manage.
So what would I do? Not use blade servers, and utilize some really cool features of Solaris 10, aka Containers/Zones. From most of what I have seen most people use blade servers for very light duty services, i.e. web servers, or part of a grid, etc. Web services can easily be moved in to a zone, as well as grid services on under utilitized servers. Especially if you use the new CoolThreads servers that Sun has. In this day where every one is trying to consolidate services and hardware, why would any one want to buy a blade system to increase the number of servers they have to manage? I am 100% about consolidating anything and everything I can. (I have 1 SunFire V890 with about 10 zones on it, and another with 5 on it. These were all seperate machines that I had to manage and patch, and now 15 has gone down to 2.)
Now the only reason I could see using a Blade server is if you could make the chassis act like a mini E25K, and make each blade be able to be part of a domain, which would allow you to tie multiple blades in to 1 logical server. Then I might be able to see a use for it, but for the most part I would stick to small 1 or 2 U servers for small applications IFF (if and only if) they would not run in a Zone.
For what’s it worth.
Technorati Tags: Blade Center, Solaris, Zones, Containers
Interesting, Rant, Solaris, Work, Zones/Containers
Interesting, Rant, Solaris, Work, Zones/Containers
