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Computing Basics for Linux
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Amazon EC2 Cost Breakdown

The following table shows the characteristics for Amazon EC2 we have identified for this web application architecture. In this example, we'll assume that you've moved into full production and you need between three and six instances. Three instances run all the time, two additional instances are required to handle peak traffic times, and another instance handles nightly backups.

Characteristic Metric Description

Clock Hours of Server Time

3 instances running 24 hours/day

2 instances running 8 hours/day

1 instances running 3 hours/day

Assuming an average of 30.5 days in a month, the full-time instances run 732 hours/month, the peak traffic instances run 244 hours/month, and the backup instances run 91.5 hours/month

Machine Characteristics

1 ti.micro instance

5 m1.small instances

Micro - 613 MB of memory, up to 2 ECUs (for short periodic bursts), EBS storage only, 32-bit or 64-bit platform

Small- 1.7 GB of memory, 1 EC2 Compute Unit (1 virtual core with 1 EC2 Compute Unit), 160 GB of local instance storage, 32-bit platform

For a list of instance types, go to http://aws.amazon.com/ec2/instance-types/.

Additional Storage

1 EBS Volume

Storage: 10 GB/Month

100 IOPS

The AMI is EBS-backed. The volume will have 10 GB provisioned storage, and 100 I/O requests per second made to the volume.

Data Transfer

Data In: 0.005 GB/day

Data Out: 0.05 GB/day

There are approximately 1,000 hits per day. Each response is about 50 KB, and each request is about 5 KB.

Instance Scale

Between 3 and 6 instances

You need 3 instances running all the time, another two to handle peak traffic, and another to handle nightly backups.

Elastic Load Balancing

Hourly usage: 732 hrs/month

Data processed: 1.525 GB/month

Elastic Load Balancing is used 24 hrs/day, 7 days/week

Elastic Load Balancing processes a total of 0.055 GB/day (data in + data out)

The following image from the AWS Simple Monthly Calculator shows the cost breakdown for Amazon EC2.

The total monthly cost is the sum of the cost of the running instances, EBS volumes and I/O requests, Elastic Load Balancer, and the data processed by the Elastic Load Balancers. Because we used basic monitoring and only one metric and alarm for our Amazon EC2 instances, there is no additional charge for Amazon CloudWatch monitoring.

Variable Formula Calculation

Instance Cost

Instance cost per hour

Number of instances

x Clock hours of server time

------------------------

$0.060

3

x 732

-------

$131.76

Instance Cost

Instance cost per hour

Number of instances

x Clock hours of server time

------------------------

$0.060

2

x 244

-------

$29.28

Instance Cost

Instance cost per hour

Number of instances

x Clock hours of server time

------------------------

$0.02

1

x 91.5

-------

$1.83

Additional Storage

Storage rate x Storage Amount (GB)

+ (I/O requests rate x seconds per month x Request rate(per 1M requests))

x Number of Volumes

--------------------------------------------------------------------------

$0.10 X 10

+ (100 x ~2.6M x $0.10)/1M

x 6

-------------------------

$164.11

Elastic Load Balancing

Hours used x Hourly rate

+ (Data processed (GB) x Process rate)

--------------------------------------

732 x $0.025

+ 1.6775 x $0.008

-----------------

$18.31

   

Total Cost Per Month

$345.29

Move on to Summing It All Up to view a summary of the total charges including AWS Data Transfer Out and the Free Usage Tier discounts.