[Jordan Olshevski (jveski)]

The Racer docs now explain what Racer gives you and when it is the right cache to pick. The concept page adds a list of key benefits, a use-case table, a comparison with running separate cache servers, and planning notes. The Gantry, Azure Blob cache, and vLLM guides and the landing page now state the main benefits for each case.

[Copilot]

🟡 Changes recommended

Unresolved documentation errors conflate placement weights with resource limits, misstate per-page ownership as a per-blob bound, and omit S3 client settings needed to avoid failed reads.

3 open issues

• Document required S3 path-style and checksum settings · New
• Clarify weights do not limit node-wide resource usage · New
• Clarify ownership is per page, not per blob · New

What changed in this PR

This documentation-only PR explains when to choose Racer as a shared cache on existing cluster nodes and highlights its benefits for common workloads.

Changes:

• Adds benefits, use cases, a dedicated-cache comparison, and planning considerations to the Racer concept page.
• Highlights workload-specific benefits in the Gantry, Azure Blob, and vLLM guides.
• Updates the landing page and architecture reference to emphasize Racer’s shared-cache model.

File	Description
docs/​layouts/​index.html	Highlights shared, encrypted caching on existing nodes.
docs/​content/​reference/​architecture.md	Expands the Racer link description to include use-case guidance.
docs/​content/​guides/​racer-vllm.md	Explains shared weight loading during replica startup.
docs/​content/​guides/​gantry.md	Adds Racer-mode benefits for image distribution.
docs/​content/​guides/​azure-blob-cache.md	Summarizes infrastructure, source-load, and client-integration benefits.
docs/​content/​concepts/​racer.md	Adds selection guidance, comparisons, planning notes, and encryption details.

_{Review effort: Balanced}

[Copilot]

🟡 Changes recommended

The documentation inaccurately describes node exclusion, recovery from corrupt cached copies, and verification timing during streaming reads, potentially misleading operators and application developers.

1 open issue

• Clarify that exclude prevents dataplane placement and membership · New

2 previously missed issues

In code that hasn't changed since last review

Describe corrupt-copy rejection and recovery, not guaranteed read failure

docs/​content/​concepts/​racer.md:56

A corrupt cached copy does not necessarily make the application's read fail. The acquisition path rejects it and can recover from another peer or an authorized origin; cmd/racer-dataplane/src/read/tests/peer_copies.rs:2333-2351 explicitly asserts a successful read in both cases. Please describe rejection and recovery instead of guaranteed failure, so readers do not expect every corruption event to surface as an application error.

Clarify SDK streams bytes before full-range verification completes

docs/​content/​concepts/​racer.md:77

This promises verification of the whole requested range before application consumption, but the SDK streams payload bytes immediately (pkg/racersdk/object.go:232-264) and withholds only the final byte pending completion (pkg/racersdk/object.go:545-582). A later page or completion failure can therefore occur after the application has consumed a prefix. Please describe the successful-completion guarantee instead, so consumers needing all-or-nothing input do not rely on verification before consumption.

3 resolved since last review

• Clarify ownership is per page, not per blob
• Clarify weights do not limit node-wide resource usage
• Document required S3 path-style and checksum settings

_{Review effort: Balanced}

[Copilot]

🟢 Approval recommended

No active review issues remain for this documentation-only update clarifying Racer’s benefits, use cases, and resource-planning guidance.

No open issues 🎉

1 resolved since last review

• Clarify that exclude prevents dataplane placement and membership

_{Review effort: Balanced}