Power consumption is a primary concern for cloud computing data centers. Being the network one of the non- negligible contributors to energy consumption in data centers, several architectures have been designed with the goal of im- proving network performance and being energy-efficient. In this paper we provide a comparison study of data center architectures, covering both classical two- and three-tier design and state-of- art ones as Jupiter, recently disclosed by Google. Specifically, we analyze the combined effect on the overall system performance of different power consumption profiles for the IT equipment and of different resource allocation policies. Our experiments, performed in small and large scale scenarios, unveil the ability of network-aware allocation policies in loading the the data center in a energy-proportional manner and the robustness of classical two- and three-tier design under network-oblivious allocation strategies.
Power Comparison Power Comparison of Cloud Data of Cloud Data Center Architectures
1. Power Comparison
of Cloud Data Center Architectures
Pietro Ruiu
Andrea Bianco, Paolo Giaccone
Claudio Fiandrino, Dzmitry Kliazovich
13th Italian Networking Workshop: San Candido, Italy
January 13 - 15, 2016
2. The quest for green data centers
• Data centers are the new polluters of 21st
century
– in 2012, accounted for 15% of the global ICT
energy consumption
– expected to increase in the next years
• Data center consumption
– 75% ICT equipment
• powering and cooling
• mostly due to servers
– 25% power distribution and facility operations
• Strong interest in designing and operating
data centers with higher energy efficiency
– not only to reduce OPEX costs
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3. Key question
• Given
• a data center topology
• a power consumption profile for each ICT device
• Define the min-power job allocation policy
• Evaluate power consumption as function of the data center
load
Classical questions
• Given
• a power consumption profile for each ICT device
• a generic job allocation policy
• Compare the power consumption behavior in function of the
data center topology
Our question
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4. Data center model
4
Data center network (DCN)
Power
Load
Power
Load
Power
Load
Servers
ICT device Power profile
5. Local vs global energy proportionality
• consume proportional to the load
• consume (and pay) only if really needed
Ideal energy proportionality
• Constant power (CONST)
• Full Energy Proportional (FEP)
• Linear (LIN)
Local power consumption for single device
• maybe very different from local power consumption
Global power consumption for overall system
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CONST
Power
Load
FEP
Power
Load
LIN
Power
Load
Power
Load
6. Global power consumption
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• N resources/devices to be allocated for a set of requests/VMs
• power consumption profile for each resource/device
• allocation policy
• consolidate: activate the minimum number of resources
• load-balance: distribute load across the resources
Resource allocation
• depends on granularity of the resources (i.e. the value of N)
• depends on allocation policy
Overall power consumption
7. Global Power Consumption
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Local power
consumption
Consolidate policy Load-balance policy
Normalized power = Power / Load
FEP
Power
Load
Power Load Load
Norm.Power
Power
Load Load
Norm.Power
CONST
Power
Load
N
Load
Power
N
Load
Power
N Load
Norm.Power N
Load
Norm.Power
• Local energy proportionality implies global energy proportionality
• If N is enough large, consolidate policy reaches global energy
proportionality for CONST local power
Local and Global Energy Proportionality
8. Our contributions
• Network-aware min-power VM online
allocation policy
• Flow-level C++ simulator of data centers
• Power comparison of different network
topologies
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• Energy profiles for each
ICT device (switch, link,
server)
• DCN topology
• VM arrival process
Flow-level
simulator
• Global power
consumption
• Load on each ICT
device
• VM blocking
probabilityVM allocation
policy
9. DCN topologies
• traditional Clos-based switch topologies
– classical 2, 3 tiers
– Jupiter
• Google’s disclosed DCN architecture
• “Jupiter Rising: A Decade of Clos Topologies and Centralized Control in
Google’s Datacenter Network”, ACM SIGCOMM CCR, Oct. 2015
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10. • Switches: 10 core sw – 18 TOR sw
• Servers 180
• Total ICT devices: 208 nodes
CORE
TOR
10Gbps40Gbps
2-tiers DCN
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13. Online VM allocation policy
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• for each VM, select a server at random
• connect through the minimum incremental DCN power
• load-balance on the servers
RSS (Random Server Selection)
• for each VM, select the server with minimum
incremental power (server + DCN)
• consolidate VMs in the same server, in the same rack, in
closeby racks, etc
• variant of min-cost Dijkstra algorithm
MNP (Minimum Network Power)
14. VM generation
• time is slotted
• at each timelot, a new VM arrives and must
communicate B bps to a previously randomly allocated
VM
– B is randomly chosen
– destination VM is chosen with Bernoulli trials
• simulation can run until saturating the data center
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VM1 VM2 VM3 VM4 VM5
15. RSS (Random Server Selection)
• small datacenter (180-192 servers)
• Jupiter appears to be the most energy proportional
– due to the larger number of switches (44 vs 27-28)
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0
5
10
15
20
25
20 30 40 50 60 70 80 90 100
NormalizedpowerperVM[W]
Data Center load [%]
3-Tier
LIN
FEP
CONST
0
5
10
15
20
25
20 30 40 50 60 70 80 90 100
Data Center load [%]
2-Tier
LIN
FEP
CONST
0
5
10
15
20
25
20 30 40 50 60 70 80 90 100
Data Center load [%]
Jupiter
LIN
FEP
CONST
16. MNP (Minimum Network Power)
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• small datacenter (180-192 servers)
• MNP allows to achieve global energy-proportionality
• under FEP, power jumps due to abrupt activation of new layers
0
0.5
1
1.5
2
2.5
3
20 30 40 50 60 70 80 90100
NormalizedpowerperVM[W]
Data Center load [%]
3-Tier
LIN
FEP
CONST
0
0.5
1
1.5
2
2.5
3
20 30 40 50 60 70 80 90 100
Data Center load [%]
2-Tier
LIN
FEP
CONST
0
0.5
1
1.5
2
2.5
3
20 30 40 50 60 70 80 90 100
Data Center load [%]
Jupiter
LIN
FEP
CONST
17. Conclusions
• Global energy proportionality of an overall data center
depends on
• local power profile of each device
• topology (number of devices)
• VM allocation policy
Take-home message
• consider large topologies with 10,000 servers
• compare data center networks given the same bisection
bandwidth
• consider the allocation of clusters of VMs
Future works
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