AWUPF Rediscovered: Atomic Writes to Unleash Pivotal Fault-Tolerance in SSDs
summary
Claim: use the SSD NVMe AWUPF atomic-write unit (commonly 4KB AWUPF) to skip journaling for small Log‑RAID metadata updates, implemented in Poseidon OS by adding per‑metadata‑page version numbers and selective direct writes. Evaluation with SPDK/FIO shows up to 3.6x random‑write throughput (and up to 73% on small async randoms), 3.3x scaling with metadata reactors, and modest gains on mixed workloads; larger updates still use conventional journaling and a versioned recovery avoids stale rollback.
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