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1. System-Wide Disablement: The tiered storage disablement feature does not aim to support the system-wide disablement of tiered storage on a cluster level, as this is controlled by the cluster-level configuration remote.log.storage.system.enable.
2. Support for Compacted Topics: Tiered Storage is not supported for compacted topics, and this behavior will remain unchanged. During re-enablement, the feature will not support tiered storage for compacted topics. When initially enabling tiered storage for a topic, we check that the topic does not have compaction enabled, however, if the topic has historically used a compaction policy, we do not perform deep check to restrict tiered storage enablement. This behavior will remain consistent during re-enablement as well.

Proposed Changes

Concepts

Remote Log Disablement Policy

When disabling tiered storage on a topic, users will have the option of retaining or deleting the remote log at the time of disablement. This is represented by a remote log disablement policy. It will be an optional policy that users can specify. By default, we will retain the remote log.

• remote.log.disable.policy=retain: Logs that are archived in the remote storage will be part of the contiguous "active" log. Clients can fetch the archived log, but no new data will be archived to the remote storage.
• remote.log.disable.policy=delete: Logs that are archived in the remote storage will not be part of the contiguous "active" log and will be deleted asynchronously as part of the disablement process.

Tiered Epoch

The tiered epoch signifies the version of a tiered storage topic. This epoch establishes a boundary for the transition from the enabling to disabling state, preventing concurrent and out-of-order modifications. Its aim is to guarantee that all activities within the disablement process are fully completed before permitting the re-enablement of tiering.

State Transitions

When users disable tiered storage on a topic, the tiered storage state on a topic transitions through the following stages: ENABLED → DISABLING → DISABLED.

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