Request-aware cooperative I/O scheduling for scale-out database applications

Hyungil Jo, Sung hun Kim, Sangwook Kim, Jinkyu Jeong, Joonwon Lee

    Research output: Contribution to conferencePaperpeer-review


    Interactive data center applications suffer from the tail latency problem. Since most modern data center applications take the sharded architecture to serve scale-out services, a request comprises multiple sub-requests handled in individual back-end nodes. Depending on the state of each back-end node, a node may issue multiple I/Os for a single sub-request. Since traditional I/O scheduling operates in an application-agnostic manner, it sometimes causes a long latency gap between the responses of sub-requests, thereby delaying the response to end-users. In this paper, we propose a request-aware cooperative I/O scheduling scheme to reduce the tail latency of a database application. Our proposed scheme captures request arrival order at the front-end of an application and exploits it to make a decision for I/O scheduling in individual back-end nodes. We implemented a prototype based on MongoDB and the Linux kernel and evaluated it with a read-intensive scan workload. Experimental results show that our proposed scheme effectively reduces the latency gap between sub-requests, thereby reducing the tail latency.

    Original languageEnglish
    Publication statusPublished - 2017
    Event9th USENIX Workshop on Hot Topics in Storage and File Systems, HotStorage 2017, co-located with USENIX ATC 2017 - Santa Clara, United States
    Duration: 2017 Jul 102017 Jul 11


    Conference9th USENIX Workshop on Hot Topics in Storage and File Systems, HotStorage 2017, co-located with USENIX ATC 2017
    Country/TerritoryUnited States
    CitySanta Clara

    Bibliographical note

    Funding Information:
    We would like to thank reviewers for their valuable comments. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. NRF-2014R1A2A1A10049626) and by Samsung Electronics. Joonwon Lee is the corresponding author.

    Publisher Copyright:
    © 2017 USENIX Association. All rights reserved.

    All Science Journal Classification (ASJC) codes

    • Hardware and Architecture
    • Information Systems
    • Software
    • Computer Networks and Communications


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