Warehouse-Scale Computers to Exploit Request-Level and Data-Level Parallelism - Computer Architecture: A Quantitative Approach - page 457

■ No contract required . In part because the costs are so low, all that is necessary to start using
EC2 is a credit card.
Figure 6.15 shows the hourly price of the many types of EC2 instances in 2011. In addition
to computation, EC2 charges for long-term storage and for Internet traffic. (There is no cost
for network traffic inside AWS regions.) Elastic Block Storage costs $0.10 per GByte per month
and $0.10 per million I/O requests. Internet traffic costs $0.10 per GByte going to EC2 and $0.08
to $0.15 per GByte leaving from EC2, depending on the volume. Puting this into historical
perspective, for $100 per month you can use the equivalent capacity of the sum of the capacit-
ies of all magnetic disks produced in 1960!
FIGURE 6.15 Price and characteristics of on-demand EC2 instances in the United
States in the Virginia region in January 2011 . Micro Instances are the newest and cheapest
category, and they offer short bursts of up to 2.0 compute units for just $0.02 per hour. Cus-
tomers report that Micro Instances average about 0.5 compute units. Cluster-Compute In-
stances in the last row, which AWS identifies as dedicated dual-socket Intel Xeon X5570 serv-
ers with four cores per socket running at 2.93 GHz, offer 10 Gigabit/sec networks. They are
intended for HPC applications. AWS also offers Spot Instances at much less cost, where you
set the price you are willing to pay and the number of instances you are willing to run, and
then AWS will run them when the spot price drops below your level. They run until you stop
them or the spot price exceeds your limit. One sample during the daytime in January 2011
found that the spot price was a factor of 2.3 to 3.1 lower, depending on the instance type.
AWS also offers Reserved Instances for cases where customers know they will use most of
the instance for a year. You pay a yearly fee per instance and then an hourly rate that is about
30% of column 1 to use it. If you used a Reserved Instance 100% for a whole year, the aver-
age cost per hour including amortization of the annual fee would be about 65% of the rate in
the first column. The server equivalent to those in Figures 6.13 and 6.14 would be a Standard
Extra Large or High-CPU Extra Large Instance, which we calculated to cost $0.11 per hour.