D2 3 Computing e-Infrastructure cost calculations and business _models_vam1-final

e-­‐FISCAL: www.efiscal.eu
EC Contract Number: 283449
much more expensive than sites >1000 cores. Indicative (median and average) values for cost per core hour are
around € 0.09 for the first category and € 0.05 for the latter.
In order to assess whether there is a statistically significant relationship between the size of the sites and the
number of FTEs, the cost per core and the cost per core hour for 2011, we have also run univariate Ordinary Least
Square Regressions. The results are shown in Appendix 7.5 and confirm that a linear relationship between cost
aspects and the size of a site in terms of CPU cores cannot be supported. However, there is a statistically
significant negative relation between the number FTEs/1,000 cores and the size of the sites in cores. Therefore,
OLS confirms the correlation results.
As a final comment, it must be noted that there are parameters that may affect the cost hour cost among
respondents. A summary of these factors follows:
• Utilisation rates: The utilisation rate (number of CPU hours actually used compared to the theoretical
maximum) plays an important role in calculating the cost per core/hour. Core hours that are not used
could be considered as are wasted resources whose cost is added to the hours been used (Hawtin et al.,
2012).
• Depreciation rates: The prolongation of hardware and auxiliary equipment useful life ends up in
decreasing the yearly cost per core CPU and the corresponding cost per core hour.
• Salaries and premises costs: These costs have a very local focus and are highly influenced by national
circumstances.
• Electricity effectiveness and cooling: The PUE of the respondents as well as the climate conditions that
prevail in the site area affect electricity consumption which in turn affects OPEX calculation.
Finally, we present the cost breakdown into CAPEX and OPEX in all our respondents.
1.2
1
0.8
0.6
0.4
0.2
Cost structure based on size
0
up to 1,000 cores between 1,000 to between 2,000 to between 5,000 to more than 10,000
2,000 cores 5,000 cores 10,000 cores cores
OPEX/TOTAL
CAPEX/TOTAL
Graph 5: CAPEX/OPEX per site based on size
The graph (Graph 5) is indicative of the fact that there is heterogeneity in the cost structure of sites/centres.
However, it is rather evident that in the vast majority of cases OPEX is not less than 40% of total costs.
e-­‐FISCAL : Financial Study for Sustainable Computing e-­‐Infrastructures
Deliverable D2.3 – Computing e-­‐Infrastructures cost estimation and analysis – Pricing and
Business models
49