Uploaded image for project: 'Core Server'
  1. Core Server
  2. SERVER-18885

Readahead startup warning is inconsistent with the documentation

    XMLWordPrintable

Details

    • Bug
    • Status: Closed
    • Major - P3
    • Resolution: Gone away
    • None
    • None
    • MMAPv1
    • None
    • ALL
    • Storage NYC 2018-10-22

    Description

      2015-06-04T10:20:40.494-0400 [initandlisten] ** WARNING: Readahead for DBPATH is set to READAHEAD_VALUE
      2015-06-04T10:20:40.494-0400 [initandlisten] **          We suggest setting it to 256KB (512 sectors) or less
      2015-06-04T10:20:40.494-0400 [initandlisten] **          http://dochub.mongodb.org/core/readahead
      

      http://dochub.mongodb.org/core/readahead links to http://docs.mongodb.org/manual/administration/production-notes/#readahead, where we recommend:

      Ensure that readahead settings for the block devices that store the database files are appropriate. For random access use patterns, set low readahead values. A readahead of 32 (16kb) often works well.
      For a standard block device, you can run sudo blockdev --report to get the readahead settings and sudo blockdev --setra <value> <device> to change the readahead settings. Refer to your specific operating system manual for more information.

      These 2 suggestions are inconsistent. We should just refer to the docs and keep our recommendation in one place.

      Attachments

        Issue Links

          Activity

            People

              gregory.wlodarek@mongodb.com Gregory Wlodarek
              joanna.cheng@mongodb.com Joanna Cheng
              Votes:
              0 Vote for this issue
              Watchers:
              7 Start watching this issue

              Dates

                Created:
                Updated:
                Resolved: