Public vs Private Cloud Usage Costs:
The StratusLab Case
Ioannis Konstantinou
Greek Research & Technology Network and
National Technical University of Athens,
ikons@cslab.ntua.gr
Evangelos Floros
Greek Research & Technology Network
efloros@grnet.gr
Nectarios Koziris
Greek Research & Technology Network and
National Technical University of Athens
nkoziris@cslab.ntua.gr
•StratusLab is co-funded by the
•European Community’s Seventh
•Framework Programme (Capacities)
•Grant Agreement INSFO-RI-261552
Q&A
How much does it cost to build your cloud?
 TCO calculation
When and how public clouds make money?
 Break even point calculation
What is cheaper: build and own a private cloud,
or renting it in Amazon?
 StratusLab case
 Actual usage traces from 11/2010 until 11/2011
•2
The StratusLab project 1/2
2 year EU funded started in June 2010
 an IaaS platform
 an open source distribution
Automatic IaaS cloud setups
Focus on automatic virtual Grid Site deployments
•3
The StratusLab Project 2/2
Disk
Marketplace
Claudia
VM• management
Management
–
of cloud
digitally
 OpenNebula
– Set
Monitoring
signed
VM
 KVM–
hypervisor
Pdisk
service
– Elasticity
– images
iSCSI
based on KPI
interface
•4
Physical Infrastructure Description
Athens datacenter completed in 2010
 4 racks with 32 servers each
 ¼ dedicated to StratusLab
 1 rack plus few TBs of EMC storage
StratusLab cloud physical machines
 18VM containers + 1FrontEnd + 4 testbed + 1 DHCP
– Dual QuadCore E5520 Xeon with Hyperthread 2x4x2=16VCPU each
– 48GB RAM and 2 RAID1 SAS Disks
– A total of 16x18=288 CPU available for VM usage
 GB Network for servers and FC with the storage
 280TB EMC Celera NS-480 storage
•5
TCO calculation
Cost Categories break-down in
Hardware and Infrastructure
Power Consumption
Manpower
•6
TCO: Hardware and Infrastructure
1/2
8K€ per server including network, storage and
dc infrastructure cost
 5 year warranty, non linear depreciation rate
 In 2 years, 60% value decrease
Server cost: 24 x 8K€ x 60%=115.2K€
Network line cost
 Flat-rate 2 x 10GbE lines result in 30K€
 Negligible GEANT network expenses
•7
TCO: Hardware and Infrastructure
2/2
Power Consumption Cost
 Monitoring period between 11/2010-11/2011
 Actual Watt measurements from VM containers using
the IPMI interfaces
 Assuming an 1.8 PUE value
 Multiplied by the energy provider’s tarrif
A total of 6.6K€ for 2 years
•8
TCO: Manpower costs
1 DC administrator with a yearly salary 40K€
 25% commitment to StratusLab for 2 years
 2 x 40 x 25% = 20K€
2 people for site admin and management
 20K€ each for 2 years resulting in
 20 x 2 x 2 = 80K€
•9
TCO summing up
€80K
€115.2K
Hardware and infrastructure
Network line leases
Power Consumption
€30K
€20K
€6.6K
Datacenter administration
Cloud site administration
• A total of 251.8K€
• Including support hardware
• Open-source software, no license fees
•10
Break-Even point calculation
Based on the calculated TCO, the hourly cost
of service hosting is
 251.8K€/(365days∙2years)/24h≈14.37€/hour
For a total of 288 cores and an average
utilization of 70%, a single core VM costs
 14.37€/(288 ∙ 0.7)=0.0712 €/core
For the above price, the cloud would amortize
its cost in two years time (zero profit)
•11
Use Case: Virtualized Grid Site
Part of the EGI under the control of GRNET
Core grid services provisioning
 A CE, 16WN, a SE with 2TB and APEL service
 Each WN has 2CPU and 4GB RAM
Since Jul 2011 support for 18VOs incl. high
energy physics (ALICE and ATLAS) biomedical
(Biomed) Com. Chemistry etc.
31,781 jobs requiring 11,655 wall clock hours
with 28,321h normalized CPU time
•12
Public Cloud Cost Analysis
Methodology
 Extract Computing, Storage and Memory consumption
stats from usage log files
 According to consumption, calculate how much it would
cost to run it on Amazon
StratusLab VM hardware resembles Amazon’s
t1.small and t1.micro instances
 t1.micro hourly rate in Dublin: 0.019€
 t1.small hourly rate in Dublin: 0.07€
 EU/Dollar rate and Amazon prices in Nov 2011
 Per hour pricing, not reserved or spot instances
•13
Charge types
CPU Cost
 EC2 cost for Amazon
 break even cost for StratusLab
Storage Cost (EBS + S3)
 No EBS, we consider local volatile disks
 No need for S3 storage
Network Cost
 Amazon Charges only for in/out traffic
 Free traffic between Amazon servers
Therefore, only CPU cost
•14
StratusLab vs Amazon Costs 1/2
70000.000 €
60000.000 €
50000.000 €
40000.000 €
30000.000 €
20000.000 €
10000.000 €
.000 €
t1.micro x
0.019€/hour
t1.small x
0.07€/hour
StratusLab VM x
0.0712€/hour
•15
StratusLab vs Amazon Costs 2/2
t1.micro is cheaper, but micro instances are
overcommitted
t1.small price the same as the break-even
By the end of the year, 20% of TCO has been
amortized
After a couple of years the full TCO will be
amortized
•16
Conclusions
A small scale private cloud is amortized in 2-3 years
In StratusLab the break-even cost for self-funding
the service is the same with EC2
 Slower amortization can achieve cheaper rates
Economies of scale
 The larger the cloud, the faster the amortization
Utilization is very important
 CPU cycles cannot be wasted
Compute-demanding apps are expensive
 Best for private clouds
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Questions?
•http://www.stratuslab.eu
•18