What happens if LFT (large file transfer) isn’t completed during the HDI large file migration window?

Document created by Amy Townsend Employee on Jan 29, 2018
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When the reason of the interruption is end of migration window, HDI won’t issue Multipart Abort. It will try to issue Multipart Complete to the temporary object. This will create a file object representing portions successfully transmitted so far.


In the next migration window, HDI will try to issue Upload Part Copy to parts if they were uploaded in the previous interrupted migration task, but were not updated during the interval of the migration tasks.


For example,


  • Object size if 2GB. LFT is enabled, part size is 5MB. There will be 400 parts.
  • Migration window is 1am-5am.
  • HDI starts migrating the object (the object path is <UUID>.tmp )
    • HDI issues Multipart Initiate operation to the object <UUID>.tmp
    • HDI issues Upload Part and Upload Part Copy operations sequentially to the object <UUID>.tmp
  • At 5am, 200 parts have been migrated. At this point, HDI runs an Multipart Complete operation on the <UUID>.tmp
  • At 1am the next day, HDI initiated a MPU to the object <UUID>.tmp with different upload ID.
    • If there’s no update in a part since last migration, HDI issues Upload Part Copy to the part with the past <UUID>.tmp as source object
    • If there’s update in a part or the part is uploaded in the last migration (e.g. the part is the 201th or later), HDI tries to issue Upload Part to the part
  • When the MPU of  the file is filled, HDI issue Multipart Complete to <UUID>.tmp object and Put Copy <UUID>.tmp to <UUID>