Help Center/ Object Storage Migration Service/ FAQs/ Product Consulting/ Why Is the Total Number or Size of Objects in the Destination Bucket Inconsistent with Those in the Source Bucket After the Migration?
Updated on 2025-12-08 GMT+08:00
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Why Is the Total Number or Size of Objects in the Destination Bucket Inconsistent with Those in the Source Bucket After the Migration?

  • Total number or size of source objects > Total number or size of destination objects
    1. Total number of source objects > Total number of destination objects

      Possible causes: New objects are added to the source bucket or the scanning result of source objects is wrong.

      Identification method: Create a migration task for the bucket again to perform an incremental migration. Check whether the number of objects scanned in the source bucket is the same as that collected by OMS during the last migration. If the numbers are inconsistent, filter the newly added source objects using the object list. If the numbers are consistent, the source object scanning result is wrong.

      Solutions: Perform an incremental migration to migrate the new objects to the destination bucket, or submit a service ticket to handle the abnormal scanning.

    2. Total size of source objects > Total size of destination objects
      Possible causes and their solutions are:
      • There are file fragments in the source bucket.

        OMS cannot migrate file fragments.

      • There are objects with multiple versions in the source bucket.

        By default, the OMS migrates only objects of the latest version. You need to manually migrate objects of older versions.

      • The source cloud vendor uses different rules for calculating object size from Huawei Cloud.

        For objects smaller than 64 KB, Huawei Cloud calculates their actual size, while some cloud vendors calculate them as 64 KB. Check the calculation rules of the source cloud vendor and whether there are source objects smaller than 64 KB.

      • There are duplicate objects in the source object list.

        OMS supports migrations using object lists or HTTP URL lists. If your list contains duplicate source objects, the same object may be detected by multiple threads as missing at the destination. This occurs because OMS uses 50 concurrent threads by default to migrate objects. As a result, the object may be uploaded multiple times. Remove duplicate objects from the list before uploading it.

  • Total number or size of source objects < Total number or size of destination objects
    1. Total number of objects

      Possible causes and their solutions are:

      • There may be a delay in calculation of object quantity by OMS and source object storage service. Please wait.
      • There are newly added objects (such as those generated after service cutover) and object lists uploaded by OMS in the destination bucket.
    2. Total size of objects

      Possible causes and their solutions are:

      • OMS stores the configuration files of the migration task in the destination bucket.

        You can delete these configuration files. The migration reports cannot be restored if these files are deleted.

      • For paused or failed tasks, OMS stores migrated file fragments in the destination bucket for future migration by default.

        You can delete these fragments from the destination bucket.

Parent topic: Product Consulting