Workload Partitioning in
Cloud Marketplaces
Ilyas Iyoob, PhDGravitant, Inc.
Ton Dieker, PhDGeorgia Institute of Technology
Aaron Yan, M.S.Gravitant, Inc.
Partitioning workloads between private and public clouds to minimize cost
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• Introduction
▫ IT Demand
▫ Conservative Cloud Approach
▫ Liberal Cloud Approach
▫ Advanced Analytics Approach
• Workload Partitioning
▫ Mathematical Formulation
▫ Cost-Optimal Solution
▫ Financial Benefits
• Conclusion
▫ Summary
Overview
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IT Demand
• Quantifying IT demand
▫ Number of servers to run your business
▫ Chart shows actual data until August 2013 followed by forecast thereafter
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Conservative Cloud Approach
Unutilized Resources
• Procure all servers through “Reservation”
▫ Pay for the servers at the beginning of the year (lower price per VM)
▫ 1 year lock-in period for each server
▫ Over-allocate servers to cover peak demand in the future
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54%
Liberal Cloud Approach
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• Procure all servers “On-Demand”
▫ Pay-as-you-go pricing (higher price per VM)
▫ No lock-in period
▫ No over-allocation
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Advanced Analytics Approach
Cloud Option Price Lock Period Price/VM/mo
On-Demand $172.8/mo 1 Month $172.8
Reserved $556/yr 12 Months $46.3
Private (128-block chassis) $660,000 120+ Months $43.0
▫ Determine how to best partition workload across three cloud options
▫ Utilize cloud option trade-offs (short lock period vs. lower price)
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Mathematical Formulation
• Model
• Decision variables and ParametersDecision Variable Unit Lock Period
𝐵𝑡: On-Demand VM 1 Month
𝑅𝑡: Reserved VM 12 Months
𝑃: Private (128-block chassis) Chassis 120+ Months
Parameters Description
𝑑𝑡 Demand for servers in month t
𝑐𝑃 Cost of purchasing a private cloud chassis
𝑐𝑅 Cost of reserving a VM (hold for one year)
𝑐𝐵 Cost of procuring one VM on-demand (hold for one month)
min𝑃,𝑅,𝐵
𝑐𝑃𝑃 + 𝑐𝑅 𝑡∈𝑇
𝑅𝑡 + 𝑐𝐵 𝑡∈𝑇
𝐵𝑡
s. t. 128𝑃 + 𝑡′=max(𝑡−11,0
𝑡
𝑅𝑡′ +𝐵𝑡 ≥ 𝑑𝑡 ∀ 𝑡 ∈ 𝑇
𝑃, 𝑅𝑡, 𝐵𝑡 ∈ 0,1,2… ∀ 𝑡 ∈ 𝑇
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Cost-Optimal Solution
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0 12 24 36 48 60 72 84 96 108 120
Num
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Months
Private Reserved On-Demand IT Demand
1%
On-demand
49%
reserved
50%
private
Financial Benefits
Liberal Approach
Partially-Conservative Approach
100%0%0%
50%0%50%
1%49%50%
$5,250,000
$3,300,000
$1,415,000
Savings ~$3,800,000
Savings ~$1,885,000
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Optimal Solution
• Dramatic financial benefits▫ Implemented work for current customers – very satisfied
▫ Our solutions are much better than traditional approaches
• Key drivers for workload partitioning▫ Demand variability
▫ Cost of on-demand cloud
Summary
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