Energy-aware control of server farms

Misikir Eyob Gebrehiwot, Samuli Aalto, Pasi Lassila

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

1 Citation (Scopus)


We study the energy-performance trade-off in server farms using multi-server models with parallel queues. Idle servers may be turned off to save energy. However, turning the server back on incurs a setup cost in the form of additional delays and energy consumption. In our model, a dispatcher assigns incoming jobs to the servers depending on the applied task (job) assignment policy. Once routed to a specific server, a job can either be queued or served immediately depending on the service discipline and state of the server. We consider a family of idle time control policies that keep track of the time spent in an idle state using a timer. Upon expiration of this timer the server is switched to a sleep state, and waits until a new job is assigned to it by the dispatcher. Earlier studies for single server systems, with Poisson arrivals, showed that the optimal control policy either leaves the server idling or switches it to sleep immediately when it becomes idle. However, in a multi-server setting, our study indicates that 10-30 % saving on the system cost can be achieved by using the right combination of idle time control and task assignment policy.

Original languageEnglish
Title of host publication2016 39th International Convention on Information and Communication Technology, Electronics and Microelectronics, MIPRO 2016 - Proceedings
Number of pages6
ISBN (Electronic)978-953-233-088-5
Publication statusPublished - 25 Jul 2016
MoE publication typeA4 Article in a conference publication
EventInternational Convention on Information and Communication Technology, Electronics and Microelectronics - Opatija, Croatia
Duration: 30 May 20163 Jun 2016
Conference number: 39


ConferenceInternational Convention on Information and Communication Technology, Electronics and Microelectronics
Abbreviated titleMIPRO

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