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b) Use the RealtimeValidationManager to fix LLC segments only has a single copy. Currently the validation manager only fix the most recent 2 segments of each partition. With this change, it will scans all segments's Zk data, if it finds a segment does not have a deep storage copy, it will instruct a server to upload the segment to the deepstorage and then updates it segment location url with the deep storage uri. c)
Failure handling
- What if deep storage upload success but the following metadata upload to controller fail?
When this happens, server commit will also fail and thus the handling is similar to the current way LLC handles committer failure. The segment completion protocol will retry commit. During the commit retry, the leader server can check if the segment already exists. If so, it will not re-upload the segment. d)
New interaction diagrams on segment completion protocol
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Compared with the existing protocol, the main differences are
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