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  1. Lustre
  2. LU-14969

Fall back to buffered I/O for unaligned direct I/O

Details

    • New Feature
    • Resolution: Won't Do
    • Minor
    • None
    • None
    • None
    • 9223372036854775807

    Description

      The SPECStorage test assumes we can do direct i/o at a 512 byte alignment boundary.  This is not the case in Lustre, since we have to be page aligned.

      The easy solution is to do what GPFS and several other file systems do:
      Fall back to buffered I/O in this case.  This is supported behavior in the kernel since at least 2.6.32.

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          is related to

          Bug - A problem which impairs or prevents the functions of the product. LU-13802 New i/o path: Buffered i/o as DIO

          • Major - Major loss of function.
          • Open

          Activity

            [LU-14969] Fall back to buffered I/O for unaligned direct I/O
            paf0186 Patrick Farrell added a comment -

            This turned out to be much harder than expected, so we're just going to do unaligned direct I/O support instead, see LU-13805

            paf0186 Patrick Farrell added a comment - This turned out to be much harder than expected, so we're just going to do unaligned direct I/O support instead, see LU-13805
            paf0186 Patrick Farrell added a comment - - edited

            "Patrick Farrell <pfarrell@whamcloud.com>" uploaded a new patch: https://review.whamcloud.com/44761/
            Subject: LU-14969 llite: DIO fall back to buffered
            Project: fs/lustre-release
            Branch: master
            Current Patch Set: 3
            Commit: 40413ac53819c8f68abb9925bcc31c844b3228b0

            paf0186 Patrick Farrell added a comment - - edited "Patrick Farrell <pfarrell@whamcloud.com>" uploaded a new patch: https://review.whamcloud.com/44761/ Subject: LU-14969 llite: DIO fall back to buffered Project: fs/lustre-release Branch: master Current Patch Set: 3 Commit: 40413ac53819c8f68abb9925bcc31c844b3228b0

            People

              paf0186 Patrick Farrell
              paf0186 Patrick Farrell
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              Dates

                Created:
                Updated:
                Resolved: