A New LSM-style Garbage Collection Scheme for ZNS SSDs
Talkat 12th USENIX Workshop on Hot Topics in Storage and File Systems (HotStorage '20) · 2020-07-13..07-14
summary
LSM_ZGC claims to cut ZNS GC latency by dividing 1GB zones into 2MB segments and using segment based fine-grained garbage collection, reading both valid and invalid data in a group manner, and merging different data into separate zones to exploit device parallelism and isolate hot/cold data. Implemented on an SK Hynix 1TB ZNS prototype (1024 zones × 1GB), it reports ~1.9× average throughput improvement (up to 2.3×) and drastically reduces candidate-zone GC time that otherwise reaches ~70–100 seconds at high utilizations.
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