hemju » AWS

Amazon EC2 Rails roundup: 2 small instances vs 1 high CPU medium instance

Helmut M. Juskewycz — Tue, 19 May 2009 17:52:38 +0000

A typical setup for a (small) web application is to have 2 tiers, one for the database and one for the application/web. Amazon EC2 offers a variety of different instances, starting form small to extra large high CPU instances. A high CPU medium instance costs double of a small instance. This raises the question, is it better (for performance) to have a cluster of 2 small instances or just one high CPU medium instance? The surprising results are presented in this post.

Disclaimer: The results are as they are. I didn’t validate them nor did I check their integrity. Please also consider that performance is just one criteria for hosting a web app.TimeWhale Time Tracking

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The 600 USD command

Helmut M. Juskewycz — Mon, 06 Apr 2009 08:56:33 +0000

I recently switched an Amazon instance to the new Amazon reserved instances price scheme. At first I was confused how to do that. Amazon doesn’t provide an interface for buying a preserved. In fact you have to use the EC2 tools and command line to do. I am comfortable to use the command line, however, I never used the command line to buy something.

First, you need to install the EC2 tools. You can find a guide here. After installing the EC2 tools, the following command lists all reserved instances:

ec2-describe-reserved-instances-offerings

This results in the following output:

OFFERING    e5a2ff3b-f6eb-4b4e-83f8-b879d7060257    us-east-1c    c1.medium    3y     1000.0    0.06    Linux/UNIX
OFFERING    248e7b75-afbc-4724-82b2-d78353299433    us-east-1b    c1.medium    3y     1000.0    0.06    Linux/UNIX
OFFERING    60dcfab3-d5b8-4d3d-9f38-480b34d38239    us-east-1a    c1.medium    3y     1000.0    0.06    Linux/UNIX
OFFERING    c48ab04c-42bb-4e5b-8c1b-c015f9604dd5    us-east-1c    c1.medium    1y     650.0    0.06    Linux/UNIX
OFFERING    ceb6a579-b754-4a50-a53e-36efdb8eb28b    us-east-1b    c1.medium    1y     650.0    0.06    Linux/UNIX
OFFERING    3a98bf7d-b94b-412a-8de5-8c77dfcc4ffd    us-east-1a    c1.medium    1y     650.0    0.06    Linux/UNIX
OFFERING    248e7b75-ed4c-4ca7-b42b-d14ee74a3360    us-east-1b    c1.xlarge    3y     4000.0    0.24    Linux/UNIX
OFFERING    ceb6a579-1420-4728-ace3-9cb73934afcf    us-east-1c    c1.xlarge    3y     4000.0    0.24    Linux/UNIX
OFFERING    60dcfab3-97dd-421b-8f75-c126de7741ce    us-east-1a    c1.xlarge    3y     4000.0    0.24    Linux/UNIX
OFFERING    ceb6a579-f9b0-4bff-994c-c62030080d27    us-east-1b    c1.xlarge    1y     2600.0    0.24    Linux/UNIX
OFFERING    4b2293b4-cb88-480b-999d-a17683faa92f    us-east-1c    c1.xlarge    1y     2600.0    0.24    Linux/UNIX
OFFERING    60dcfab3-fa53-4d32-97cc-2fd1a0a8c0ac    us-east-1a    c1.xlarge    1y     2600.0    0.24    Linux/UNIX
OFFERING    649fd0c8-8bd3-489e-904c-4c5dfcb131ea    us-east-1b    m1.large    3y     2000.0    0.12    Linux/UNIX
OFFERING    248e7b75-5324-48e5-9749-fd3b4de01829    us-east-1a    m1.large    3y     2000.0    0.12    Linux/UNIX
OFFERING    d586503b-6876-4d40-8f94-1b2dde6b0ead    us-east-1c    m1.large    3y     2000.0    0.12    Linux/UNIX
OFFERING    248e7b75-a817-462e-996a-8ea7b4810a0e    us-east-1b    m1.large    1y     1300.0    0.12    Linux/UNIX
OFFERING    c48ab04c-280c-4879-8119-63ac87002498    us-east-1a    m1.large    1y     1300.0    0.12    Linux/UNIX
OFFERING    649fd0c8-4af1-4f63-bbdb-1a05951886a4    us-east-1c    m1.large    1y     1300.0    0.12    Linux/UNIX
OFFERING    3a98bf7d-96c3-4d2f-a263-123fa6b46d61    us-east-1b    m1.small    3y     500.0    0.03    Linux/UNIX
OFFERING    248e7b75-0799-4a55-a0cb-f8d28eb11921    us-east-1a    m1.small    3y     500.0    0.03    Linux/UNIX
OFFERING    438012d3-d93c-4fbd-a245-33b4bf0930ec    us-east-1c    m1.small    3y     500.0    0.03    Linux/UNIX
OFFERING    60dcfab3-a56c-4092-8c90-3677e9da02b7    us-east-1b    m1.small    1y     325.0    0.03    Linux/UNIX
OFFERING    4b2293b4-1e6c-4eb3-ab74-4493c0e57987    us-east-1a    m1.small    1y     325.0    0.03    Linux/UNIX
OFFERING    c48ab04c-c057-457e-a4d8-a0f172f4db2d    us-east-1c    m1.small    1y     325.0    0.03    Linux/UNIX
OFFERING    c48ab04c-6769-4bc1-966e-f7b0326001dd    us-east-1b    m1.xlarge    3y     4000.0    0.24    Linux/UNIX
OFFERING    649fd0c8-4767-43a1-a530-b4a1f0c08c31    us-east-1a    m1.xlarge    3y     4000.0    0.24    Linux/UNIX
OFFERING    d586503b-20ad-4beb-bc88-60a1333c2b98    us-east-1c    m1.xlarge    3y     4000.0    0.24    Linux/UNIX
OFFERING    e5a2ff3b-8646-4f48-912a-aaeba5823c73    us-east-1b    m1.xlarge    1y     2600.0    0.24    Linux/UNIX
OFFERING    c48ab04c-63ab-4cd6-b8f5-978a29eb9bcc    us-east-1a    m1.xlarge    1y     2600.0    0.24    Linux/UNIX
OFFERING    c48ab04c-119e-41f1-8b0f-b83c4fc4f869    us-east-1c    m1.xlarge    1y     2600.0    0.24    Linux/UNIX

So, to reserve one small instance in the us-east-1a region, just type

ec2-purchase-reserved-instances-offering -c 1 -o 248e7b75-0799-4a55-a0cb-f8d28eb11921

then press enter and you are credited 500 USD plus 100 USD taxes. However, in 300 days the command pays for itself.

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Amazon EC2 preserved instances pricing scheme

Helmut M. Juskewycz — Mon, 06 Apr 2009 08:29:21 +0000

Standard rates

Standard On-Demand Instances	Linux/UNIX Usage
Small (Default)	$0.10 per hour
Large	$0.40 per hour
Extra Large	$0.80 per hour
High CPU On-Demand Instances	Linux/UNIX Usage
Medium	$0.20 per hour
Extra Large	$0.80 per hour

Reserved rates

Linux/UNIX	One-time Fee
Standard Reserved Instances	1 yr Term	3 yr Term	Usage
Small (Default)	$325	$500	$0.03 per hour
Large	$1300	$2000	$0.12 per hour
Extra Large	$2600	$4000	$0.24 per hour
High CPU Reserved Instances	1 yr Term	3 yr Term	Usage
Medium	$650	$1000	$0.06 per hour
Extra Large	$2600	$4000	$0.24 per hour

Conclusion

It is pretty easy to calculate the break even. Divide the initial costs by the difference of the hourly rates, so you will get the break even in hours. Actually, Amazon has a scheme behind the calculation and so the break even is the same for all instances and only varies between the terms. If you take a 1 year term, the break even in days is 194, and for a 3 year term it is 298 days.

One last thing, All prices are excluding taxes (20 %) and one ceaveat. Amazon doesn’t provide invoices. Yes, if you pay AWS products, you don’t get an invoice, just a usage report. The horror for all accountants.

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