{"title":"ZNS SSD终身级lsm树压缩","authors":"Jeeyoon Jung, Dongkun Shin","doi":"10.1145/3538643.3539741","DOIUrl":null,"url":null,"abstract":"The Log-Structured Merge (LSM) tree is considered well-suited to zoned namespace (ZNS) storage devices since the write requests to LSM-tree is sequential. However, zones can be partially invalidated and be fragmented during LSM-tree compaction. The partially-invalid zones cannot be utilized and thus space amplification becomes significant. To reclaim the invalid space, host-managed garbage collection (GC) is required, which increases the write amplification of ZNS storage and degrades I/O performance. We introduce a lifetime-leveling compaction (LL-compaction) tailored for ZNS SSD, which can alleviate space amplification without GC by making the sorted string tables in a zone have similar lifetimes. In our experiments using LevelDB, the LL-compaction achieved 1.7x better performance by removing GCs.","PeriodicalId":159120,"journal":{"name":"Proceedings of the 14th ACM Workshop on Hot Topics in Storage and File Systems","volume":"31 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"9","resultStr":"{\"title\":\"Lifetime-leveling LSM-tree compaction for ZNS SSD\",\"authors\":\"Jeeyoon Jung, Dongkun Shin\",\"doi\":\"10.1145/3538643.3539741\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The Log-Structured Merge (LSM) tree is considered well-suited to zoned namespace (ZNS) storage devices since the write requests to LSM-tree is sequential. However, zones can be partially invalidated and be fragmented during LSM-tree compaction. The partially-invalid zones cannot be utilized and thus space amplification becomes significant. To reclaim the invalid space, host-managed garbage collection (GC) is required, which increases the write amplification of ZNS storage and degrades I/O performance. We introduce a lifetime-leveling compaction (LL-compaction) tailored for ZNS SSD, which can alleviate space amplification without GC by making the sorted string tables in a zone have similar lifetimes. In our experiments using LevelDB, the LL-compaction achieved 1.7x better performance by removing GCs.\",\"PeriodicalId\":159120,\"journal\":{\"name\":\"Proceedings of the 14th ACM Workshop on Hot Topics in Storage and File Systems\",\"volume\":\"31 1\",\"pages\":\"0\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2022-06-27\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"9\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Proceedings of the 14th ACM Workshop on Hot Topics in Storage and File Systems\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1145/3538643.3539741\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Proceedings of the 14th ACM Workshop on Hot Topics in Storage and File Systems","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1145/3538643.3539741","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
The Log-Structured Merge (LSM) tree is considered well-suited to zoned namespace (ZNS) storage devices since the write requests to LSM-tree is sequential. However, zones can be partially invalidated and be fragmented during LSM-tree compaction. The partially-invalid zones cannot be utilized and thus space amplification becomes significant. To reclaim the invalid space, host-managed garbage collection (GC) is required, which increases the write amplification of ZNS storage and degrades I/O performance. We introduce a lifetime-leveling compaction (LL-compaction) tailored for ZNS SSD, which can alleviate space amplification without GC by making the sorted string tables in a zone have similar lifetimes. In our experiments using LevelDB, the LL-compaction achieved 1.7x better performance by removing GCs.