-Re: Could an EC2 machine to 4 times slower than local dev workstation?
Bryan Beaudreault 2011-12-30, 16:54
We have also seen this in our testing, though we focused mainly on MR more
Keep in mind that EC2 Compute Units are defined as follows:
The amount of CPU that is allocated to a particular instance is expressed
> in terms of these EC2 Compute Units. We use several benchmarks and tests to
> manage the consistency and predictability of the performance of an EC2
> Compute Unit. One EC2 Compute Unit provides the equivalent CPU capacity of
> a 1.0-1.2 GHz 2007 Opteron or 2007 Xeon processor.
This does not even account for CPU contention that Amandeep mentioned,
which we have noticed at times as well. Also, c1.mediums have a I/O
Performance rating of "Moderate." I think this mainly refers to ethernet
speed, but it could refer to disk speed as well.
If your local workstation is a reasonably modern system, it is very
possible for you to see much better performance locally. The difference
between 2.5 1.0 GHz 2007 processors (2.5 compute units) and a modern i5,
i7, or equivalent is huge not just in speed and number of cores, but
architecture, cache, etc. In terms of HBase write speed, if you are
running on an SSD this could cause a substantial gap as well.
On Fri, Dec 30, 2011 at 12:38 AM, Amandeep Khurana <[EMAIL PROTECTED]> wrote:
> Is your client program running on the same node? Given that c1.mediums are
> on shared hosts, your neighbor might be overloading his VM, causing yours
> to starve.
> On Fri, Dec 30, 2011 at 9:50 AM, Mark Kerzner <[EMAIL PROTECTED]>
> > Hi,
> > I am running a small program to load about 1 million rows into HBase. It
> > takes 200 seconds on my dev machine, and 800 seconds on a c1.medium EC2
> > machine. Both are running the same version of Ubuntu and the same version
> > of HBase. Everything is local on one machine in both cases.
> > What could the difference between the two environments be? I did notice
> > that my local machine has higher CPU loads:
> > hbase 64%
> > java (my app) 38%
> > hdfs 20%
> > whereas the EC2 machine
> > hbase 47%
> > java (my app) 23%
> > hdfs 14%
> > Sincerely,
> > Mark