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  1. Lustre
  2. LU-9252

osd: Cannot really disable cache on OSS

Details

    • Improvement
    • Resolution: Duplicate
    • Minor
    • None
    • None
    • 3
    • 9223372036854775807

    Description

      When deactivating caching on an OSS through the osd proc files: read_cache_enable and writethrough_cache_enable, it only simulates Lustre's behaviour without cache.

      It would be interesting though, for Lustre's OSSes to be able to allocate their memory outside of the pagecache for it seems to be a performance issues when using SSD disks: it creates a CPU overload and 65% of CPU ressources are spent to allocate/free memory from the pagecache.

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        Issue Links

          is related to

          Improvement - An improvement or enhancement to an existing feature or task. LU-11347 Do not use pagecache for SSD I/O when read/write cache are disabled

          • Major - Major loss of function.
          • Resolved

          Activity

            [LU-9252] osd: Cannot really disable cache on OSS
            pjones Peter Jones made changes -
            Reporter Original: Quentin Bouget [ bougetq ] New: CEA [ cealustre ]
            adilger Andreas Dilger made changes -
            Resolution New: Duplicate [ 3 ]
            Status Original: Open [ 1 ] New: Resolved [ 5 ]
            bougetq Quentin Bouget (Inactive) made changes -
            Link New: This issue is related to LU-11347 [ LU-11347 ]
            pjones Peter Jones made changes -
            Assignee Original: WC Triage [ wc-triage ] New: Peter Jones [ pjones ]
            pjones Peter Jones made changes -
            Issue Type Original: Bug [ 1 ] New: Improvement [ 4 ]
            bzzz Alex Zhuravlev made changes -
            Description Original: When deactivating caching on an OSS through the osd proc files: {{read_cache_enable}} and {{writethrough_cache_enable}}, it only simulates Lustre's behaviour without cache.

            It would be interesting though, for Lustre's OSSes to be able to allocate their memory outside of the pagecache for it seems to be a performance issues when using SSD disks: it creates a CPU overload and 65% of CPU ressources are spent to allocate/free memory from the pagecache.             		New:  When deactivating caching on an OSS through the osd proc files: {{read_cache_enable}} and {{writethrough_cache_enable}}, it only simulates Lustre's behaviour without cache.

            It would be interesting though, for Lustre's OSSes to be able to allocate their memory outside of the pagecache for it seems to be a performance issues when using SSD disks: it creates a CPU overload and 65% of CPU ressources are spent to allocate/free memory from the pagecache.
            bougetq Quentin Bouget (Inactive) created issue -

            People

              pjones Peter Jones
              cealustre CEA
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              Dates

                Created:
                Updated:
                Resolved: