Details
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Technical task
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Resolution: Fixed
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Minor
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None
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None
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9223372036854775807
Description
In DNE environment, the object and its name entry may reside on different MDTs. Under such case, we will create an agent object on the MDT where the name entry resides. The agent object is empty to indicates that the real object for this name entry resides on another MDT. If without agent object, related name entry will be skipped when perform MDT side file level backup/restore via ZPL by userspace tool, such as 'tar'.
ldiskfs supports agent object. After migrated to ZFS, the agent object will be on ZFS backend. ZFS needs to handle it to avoid leak. So supporting agent object is necessary if want to backup/restore ZFS via ZPL, or migrate ZFS to ldiskfs.
On the other hand, although ldiskfs supports agent object, but for regular-file, too much agent objects is not a good solution. We will consider to share agent object for multiple remote reference case.