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- The commit leader becomes the owner of the segment being committed. It will make this segment downloadable using a new HTTP end point. After the leader commits the segment metadata, it uploads the segment to the configured deep storage as a backup. The deep storage uri will be added to the segment location list in controller.
- Similarly other replicas will keep updating this 'segment location' via the Controller.
- When the controller asks a server to download the segment for whatever reason, the server will check the segment location list. It will first try to download it from a deep storage uri to minimize the impact on servers. If there is no such uri, it will go down the list of servers to download the segment.
- All existing error handling routines remain unchanged.
Pros:
- Simple to implement
- No coordination needed.
- Minimal changes to the current controller/server FSMs used in the LLC segment protocols: some noticeable changes would be in the controller FSM – the Committer Uploading state now becomes obsolete for obvious reason and should be generalized to a state which reflects the segment is being persisted.
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