Mean-field-analysis of coding versus replication in cloud storage systems

Bin Li, Aditya Ramamoorthy, R. Srikant

Research output: Chapter in Book/Report/Conference proceedingConference contribution


We study cloud-storage systems with a very large number of files stored in a very large number of servers. In such systems, files are either replicated or coded to ensure reliability, i.e., file recovery from server failures. This redundancy in storage can further be exploited to improve system performance (mean file access delay) through appropriate load-balancing (routing) schemes. However, it is unclear whether coding or replication is better from a system performance perspective since the corresponding queueing analysis of such systems is, in general, quite difficult except for the trivial case when the system load asymptotically tends to zero. Here, we study the more difficult case where the system load is not asymptotically zero. Using the fact that the system size is large, we obtain a mean-field limit for the steady-state distribution of the number of file access requests waiting at each server. We then use the mean-field limit to show that, for a given storage capacity per file, coding strictly outperforms replication at all traffic loads while improving reliability. Further, the factor by which the performance improves in the heavy-traffic is at least as large as in the light-traffic case. Finally, we validate these results through extensive simulations.

Original languageEnglish (US)
Title of host publicationIEEE INFOCOM 2016 - 35th Annual IEEE International Conference on Computer Communications
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781467399531
StatePublished - Jul 27 2016
Event35th Annual IEEE International Conference on Computer Communications, IEEE INFOCOM 2016 - San Francisco, United States
Duration: Apr 10 2016Apr 14 2016

Publication series

NameProceedings - IEEE INFOCOM
ISSN (Print)0743-166X


Other35th Annual IEEE International Conference on Computer Communications, IEEE INFOCOM 2016
Country/TerritoryUnited States
CitySan Francisco

ASJC Scopus subject areas

  • General Computer Science
  • Electrical and Electronic Engineering


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