PR #6008 deleted crates/io-metrics/src/config.rs but the crate docs still taught the deleted API: both READMEs kept the Unified Configuration sections, module-tree entries and ./src/config.rs links, the example kept an orphaned numbered comment, and the io-core/io-metrics changelog had no removal record. Scrub all of it; keep cache_config.rs references, which are still real.
crates/io-metrics/src/config.rs was a near-copy of io-core's Backpressure/Deadlock configuration with already-drifted field names (high_watermark vs io-core's high_water_mark) and had no consumer outside the crate's own example: the canonical BackpressureConfig lives in crates/io-core/src/backpressure.rs. Delete the module, its lib.rs re-exports, and the example's unified-config section, and settle the corresponding ARCHITECTURE.md ledger line that tracked this copy's removal.
Ref rustfs/backlog#1833 (PR4).
Zhengchao An