Nereus

Product line: V2 on main at 0.2.0-SNAPSHOT. The current V2 milestone is documentation/readiness work; existing Java and runtime evidence remain V1 residue until a V2 milestone explicitly replaces and promotes them.

Nereus V2 is a multi-protocol Storage Fabric with independent Kafka and Pulsar Protocol Cells. It combines protocol-native position and control authority with shared storage-lifecycle contracts and three Storage Epoch profiles:

• OBJECT_WAL: cost-first; ACK waits for verified durable Object WAL coverage;
• BOOKKEEPER_WAL_ONLY: performance-first; ACK waits for BookKeeper quorum and performs no Object offload;
• BOOKKEEPER_WAL_ASYNC_OBJECT: performance-first; ACK waits for BookKeeper quorum and sealed protocol coverage is offloaded asynchronously.

Kafka Offset and Pulsar Position remain separate truths. Shared storage uses typed Protocol Coverage and Physical Extents; it does not introduce a universal logical offset or a second native write authority.

Documentation

Current V2 authority:

1. V2 design index
2. Overall architecture
3. Context map and domain glossaries
4. Implementation plan and gates
5. Accepted decisions

Historical V1 design, Phase/Future contracts, release evidence, and delivery history are isolated under the V1 archive. The exact V1 product line is preserved at v0.1@a14d925da5763f36208f8ddca7bef31f3eb90b0b; V1 documents are never V2 architecture or current-source V2 evidence.

Release-independent freeze and tag procedures remain under docs/releases.

Repository layout

nereus/
  docs/v2/          current V2 architecture, contracts, scenarios, open questions, and Grill records
  docs/v1/          frozen V1 design, Phase/Future contracts, performance notes, and release evidence
  docs/decisions/   repository-wide, V1/V2 transition, and accepted V2 decisions
  docs/releases/    product-line-neutral release freeze and tag process
  nereus-*/         current source graph; V1 residue until replaced by explicit V2 milestones

Verification

The V2 documentation baseline is executable:

./gradlew v2M0Check

The ordinary repository build remains available while M1 constructs and promotes the pure V2 graph:

./gradlew check

Historical V1 gates remain runnable only as explicitly labeled evidence while their corresponding source slices still exist on main. Passing a V1 gate does not promote V2 implementation or evidence status.