{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,29]],"date-time":"2026-03-29T01:14:26Z","timestamp":1774746866216,"version":"3.50.1"},"reference-count":28,"publisher":"Association for Computing Machinery (ACM)","issue":"2","license":[{"start":{"date-parts":[[2024,5,21]],"date-time":"2024-05-21T00:00:00Z","timestamp":1716249600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Key Research and Development Program of China","award":["2022YFB4500302"],"award-info":[{"award-number":["2022YFB4500302"]}]},{"name":"Alibaba Research Fellow Project","award":["CCT62WHZ1220002-16611630-1"],"award-info":[{"award-number":["CCT62WHZ1220002-16611630-1"]}]}],"content-domain":{"domain":["dl.acm.org"],"crossmark-restriction":true},"short-container-title":["ACM Trans. Archit. Code Optim."],"published-print":{"date-parts":[[2024,6,30]]},"abstract":"<jats:p>Object storage has been widely used in the cloud. Traditionally, the size of object metadata is much smaller than that of object data, and thus existing object storage systems (such as Ceph and Oasis) can place object data and metadata, respectively, on hard disk drives (HDDs) and solid-state drives (SSDs) to achieve high I\/O performance at a low monetary cost. Currently, however, a wide range of cloud applications organize their data as large numbers of small objects of which the data size is close to (or even smaller than) the metadata size, thus greatly increasing the cost if placing all metadata on expensive SSDs.<\/jats:p>\n          <jats:p>\n            This article presents x\n            <jats:sc>Meta<\/jats:sc>\n            , an SSD-HDD-hybrid optimization for metadata maintenance of cloud-scale object storage. We observed that a substantial portion of the metadata of small objects is rarely accessed and thus can be stored on HDDs with little performance penalty. Therefore, x\n            <jats:sc>Meta<\/jats:sc>\n            first classifies the\n            <jats:italic>hot<\/jats:italic>\n            and\n            <jats:italic>cold<\/jats:italic>\n            metadata based on the frequency of metadata accesses of upper-layer applications and then adaptively stores the hot metadata on SSDs and the cold metadata on HDDs. We also propose a merging mechanism for hot metadata to further improve the efficiency of SSD storage and optimize range key query and insertion for hot metadata by designing composite keys. We have integrated the x\n            <jats:sc>Meta<\/jats:sc>\n            metadata service with Ceph to realize a high-performance, low-cost object store (called xCeph). The extensive evaluation shows that xCeph outperforms the original Ceph by an order of magnitude in the space requirement of SSD storage, while improving the throughput by up to 2.7\u00d7.\n          <\/jats:p>","DOI":"10.1145\/3652606","type":"journal-article","created":{"date-parts":[[2024,3,13]],"date-time":"2024-03-13T11:52:41Z","timestamp":1710330761000},"page":"1-20","update-policy":"https:\/\/doi.org\/10.1145\/crossmark-policy","source":"Crossref","is-referenced-by-count":4,"title":["x\n            <scp>Meta<\/scp>\n            : SSD-HDD-hybrid Optimization for Metadata Maintenance of Cloud-scale Object Storage"],"prefix":"10.1145","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0009-0002-1110-5177","authenticated-orcid":false,"given":"Yan","family":"Chen","sequence":"first","affiliation":[{"name":"Tsinghua University, Beijing, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3733-5456","authenticated-orcid":false,"given":"Qiwen","family":"Ke","sequence":"additional","affiliation":[{"name":"NICEX Lab, Xiamen, China"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-1344-6552","authenticated-orcid":false,"given":"Huiba","family":"Li","sequence":"additional","affiliation":[{"name":"Alibaba Group, Hangzhou, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6651-7032","authenticated-orcid":false,"given":"Yongwei","family":"Wu","sequence":"additional","affiliation":[{"name":"Tsinghua University, Beijing, China and Quan Cheng Laboratory, Jinan, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6450-8485","authenticated-orcid":false,"given":"Yiming","family":"Zhang","sequence":"additional","affiliation":[{"name":"NICE xLab, XMU, Xiamen, China"}]}],"member":"320","published-online":{"date-parts":[[2024,5,21]]},"reference":[{"key":"e_1_3_2_2_2","unstructured":"Ceph Team. Ceph Object Gateway. https:\/\/docs.ceph.com\/en\/pacific\/radosgw"},{"key":"e_1_3_2_3_2","doi-asserted-by":"publisher","DOI":"10.14778\/3415478.3415560"},{"key":"e_1_3_2_4_2","doi-asserted-by":"crossref","unstructured":"Qing Zheng Haopeng Chen Yaguang Wang Jiangang Duan and Zhiteng Huang. 2012. Cosbench: A benchmark tool for cloud object storage services. In 2012 IEEE Fifth International Conference on Cloud Computing. 998\u2013999.","DOI":"10.1109\/CLOUD.2012.52"},{"issue":"2007","key":"e_1_3_2_5_2","first-page":"21","article-title":"The Hadoop distributed file system: Architecture and design","volume":"11","author":"Borthakur Dhruba","year":"2007","unstructured":"Dhruba Borthakur. 2007. The Hadoop distributed file system: Architecture and design. Hadoop Proj. Website 11, 2007 (2007), 21.","journal-title":"Hadoop Proj. Website"},{"key":"e_1_3_2_6_2","doi-asserted-by":"publisher","DOI":"10.14778\/3476311.3476385"},{"key":"e_1_3_2_7_2","doi-asserted-by":"publisher","DOI":"10.1109\/HPCC.2008.86"},{"key":"e_1_3_2_8_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.future.2012.08.015"},{"key":"e_1_3_2_9_2","doi-asserted-by":"publisher","DOI":"10.1109\/ICCD50377.2020.00077"},{"key":"e_1_3_2_10_2","doi-asserted-by":"publisher","DOI":"10.1145\/3302424.3303967"},{"key":"e_1_3_2_11_2","doi-asserted-by":"publisher","DOI":"10.1145\/3033273"},{"key":"e_1_3_2_12_2","doi-asserted-by":"publisher","DOI":"10.1109\/ICDCS.2018.00021"},{"key":"e_1_3_2_13_2","first-page":"313","volume-title":"20th USENIX Conference on File and Storage Technologies (FAST\u201922)","author":"Lv Wenhao","year":"2022","unstructured":"Wenhao Lv, Youyou Lu, Yiming Zhang, Peile Duan, and Jiwu Shu. 2022. InfiniFS: An efficient metadata service for large-scale distributed filesystems. In 20th USENIX Conference on File and Storage Technologies (FAST\u201922). 313\u2013328."},{"key":"e_1_3_2_14_2","doi-asserted-by":"publisher","DOI":"10.12700\/APH.18.5.2021.5.12"},{"key":"e_1_3_2_15_2","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-030-67731-2_40"},{"key":"e_1_3_2_16_2","first-page":"117","volume-title":"USENIX Annual Technical Conference (USENIX ATC\u201923)","author":"Oh Myoungwon","year":"2023","unstructured":"Myoungwon Oh, Sungmin Lee, Samuel Just, Young Jin Yu, Duck-Ho Bae, Sage Weil, Sangyeun Cho, and Heon Y Yeom. 2023. TiDedup: A new distributed deduplication architecture for Ceph. In USENIX Annual Technical Conference (USENIX ATC\u201923). 117\u2013131."},{"key":"e_1_3_2_17_2","article-title":"The raft consensus algorithm","volume":"190","author":"Ongaro Diego","year":"2015","unstructured":"Diego Ongaro and John Ousterhout. 2015. The raft consensus algorithm. Lecture Notes CS 190 (2015).","journal-title":"Lecture Notes CS"},{"key":"e_1_3_2_18_2","unstructured":"RocksDB Team. A persistent key-value store for fast storage environments. [n. d.]. Retrieved from https:\/\/rocksdb.org\/"},{"key":"e_1_3_2_19_2","doi-asserted-by":"publisher","DOI":"10.1145\/3132747.3132765"},{"key":"e_1_3_2_20_2","doi-asserted-by":"publisher","DOI":"10.1145\/2628194.2628195"},{"key":"e_1_3_2_21_2","doi-asserted-by":"publisher","DOI":"10.1007\/s10844-020-00608-7"},{"key":"e_1_3_2_22_2","unstructured":"MinIO Team. The Object Store for AI Data Infrastructure. https:\/\/min.io\/"},{"key":"e_1_3_2_23_2","unstructured":"Swift Team. OpenStack Swift. https:\/\/github.com\/openstack\/swift?tab=readme-ov-file"},{"key":"e_1_3_2_24_2","first-page":"307","volume-title":"7th Symposium on Operating Systems Design and Implementation","author":"Weil Sage A.","year":"2006","unstructured":"Sage A. Weil, Scott A. Brandt, Ethan L. Miller, Darrell D. E. Long, and Carlos Maltzahn. 2006. Ceph: A scalable, high-performance distributed file system. In 7th Symposium on Operating Systems Design and Implementation. 307\u2013320."},{"key":"e_1_3_2_25_2","unstructured":"Song Xiaodong. 2017. Study on performance of storing small files in Hadoop distributed file system. Master Dissertation. Beijing Jiaotong University (2017)."},{"issue":"10","key":"e_1_3_2_26_2","first-page":"76","article-title":"Cao sheng. Storage research of small files in massive education resource","volume":"42","author":"Xiaorong You","year":"2015","unstructured":"You Xiaorong. 2015. Cao sheng. Storage research of small files in massive education resource. Comput. Sci. 42, 10 (2015), 76\u201380.","journal-title":"Comput. Sci."},{"key":"e_1_3_2_27_2","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-319-11194-0_5"},{"key":"e_1_3_2_28_2","doi-asserted-by":"publisher","DOI":"10.1109\/EDGE.2019.00031"},{"key":"e_1_3_2_29_2","doi-asserted-by":"publisher","DOI":"10.1145\/3568424"}],"container-title":["ACM Transactions on Architecture and Code Optimization"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dl.acm.org\/doi\/10.1145\/3652606","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/dl.acm.org\/doi\/pdf\/10.1145\/3652606","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,6,19]],"date-time":"2025-06-19T00:03:30Z","timestamp":1750291410000},"score":1,"resource":{"primary":{"URL":"https:\/\/dl.acm.org\/doi\/10.1145\/3652606"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,5,21]]},"references-count":28,"journal-issue":{"issue":"2","published-print":{"date-parts":[[2024,6,30]]}},"alternative-id":["10.1145\/3652606"],"URL":"https:\/\/doi.org\/10.1145\/3652606","relation":{},"ISSN":["1544-3566","1544-3973"],"issn-type":[{"value":"1544-3566","type":"print"},{"value":"1544-3973","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,5,21]]},"assertion":[{"value":"2023-09-03","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2024-02-27","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2024-05-21","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}