Amazon measures its CPU allocation in terms of virtual core and EC2 compute unit. EC2 Compute Units are defined as:
The amount of CPU allocated for a particular example is expressed in terms of these EC2 compute unit. We use several standards and tests to determine the stability and forecast of performance from an EC2 Compute Unit. An EC2 compute unit provides the same CPU capability of a 1.0-1.2 GHz 2007 optron or 2007 XOn processor. This is equivalent to an initial-2006 1.7 GHz Xeon processor referred to in our original document.
My question is, I have a "big example" that is "4 EC2 compute units (2 EC 2 compute units with 2 virtual core each)". Does it mean that the core 4 core is in a logical sense? Do I want to create 4 CPU-bound threads? Or is the calculation unit a measure of power only, and I have 2 cores?
In addition, given the scalability of the server, would it be better to double the computing power of a box and hosting the database and the server on the same box? Or do I have 2 different, weaker boxes?
nicolides are correct, small examples are small one core, the remaining two core measurements of the compute unit As defined by the following:
An EC2 Compute Unit (ECU) 1.0-1.2 GHz 2007 offers the same CPU capability of the 2007 Option or Processor Processor.
I run on a small incident, with both the web server and the database hosted on a virtual machine. I am impressed with the performance, but again there is no heavy load on it.
If you are taking care of whatever you are bumper for your money, I will try with your setup to run on the same small example (1 core, 1 EC2 unit $ 0.10 / hour) Both the servers and see how it stacks up. In the next stage, a high-CPU medium example (2 cores, 5 total EC 2 units will be $ 0.20 / hour). Unless you really want to kill your servers, I'm sure you will be able to run them on that single medium example. Only two times in the price of small examples, you get five times the performance, which is better than running two small examples.
One thing is that small and high-CPU medium examples are 32-bit, where all other (large, extra large and high-CPU extra large) 64-bit are 64-bit instances But 32-bit Amazon machine can not run the image, and vice versa. If you are working with stock AMI, then this is not a problem because you will usually be able to get both versions, but for a custom image it can do a little bit more work for you.
Comments
Post a Comment