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  1. Couchbase Server
  2. MB-7627

Draining rate drops and becomes choppy when more than 5% cache miss happens

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 3.0
    • Fix Version/s: 2.1.0
    • Component/s: couchbase-bucket
    • Security Level: Public
    • Labels:
      None
    • Environment:
      2.0.1 enterprise edition (build-144) on Centos

      Description

      3 node cluster, 4 cores, 8G RAM for each node. The disk is 30G HHD.
      Create a default bucket with 3.5G RAM.
      Initial Load 35M items to make the cluster into 75% resident ratio and when access the data the workload definition is:
      create:10, update:30, get:50, delete:10,ops per sec:30000

      When many background fetches happen, cache miss around 5%~10%, contention to the disk write queue between threads make the draining rate drop significantly and choppy.

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        Activity

        Hide
        chiyoung Chiyoung Seo added a comment -

        Jin,

        This issue should be investigated as part of our effort to enhance the disk write performance.

        It seems to me that there is a high contention between bg fetcher and flusher in case of a high cache miss ratio (5%)

        Show
        chiyoung Chiyoung Seo added a comment - Jin, This issue should be investigated as part of our effort to enhance the disk write performance. It seems to me that there is a high contention between bg fetcher and flusher in case of a high cache miss ratio (5%)

          People

          • Assignee:
            ronnie Ronnie Sun (Inactive)
            Reporter:
            Chisheng Chisheng Hong (Inactive)
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            Dates

            • Created:
              Updated:
              Resolved:

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