Optimizing FTL mapping cache for random-write workloads using adaptive block partitioning

Li-Pin Chang, Sheng Min Huang, Wen Ping Li

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Mapping table caching is a promising technique to reduce the RAM footprint of the FTL mapping tables in modern SSDs. The mapping cache can achieve a high hit ratio under the disk workloads of many production systems because there are spatial and temporal localities in the disk workloads. However, the mapping cache suffers from severe miss penalty and degrades the SSD performance under random write patterns, which are common in benchmarks and database applications. Our main result is that optimizing the mapping cache for random-write workloads is completely different from that for non-random workloads. We propose partitioning all flash blocks into a group of user data and a group of mapping information. By strategically shifting free flash blocks between the two groups, the best balance of the garbage collection overhead between the two groups is achieved. We conducted a series of experiments using the disk workloads from industry-standard SSD benchmarks, and the results show that our approach improved the write performance by up to 30% compared to a conventional map caching method.

Original languageEnglish
Title of host publicationProceedings of the 29th Annual ACM Symposium on Applied Computing, SAC 2014
PublisherAssociation for Computing Machinery
Pages1504-1510
Number of pages7
ISBN (Print)9781450324694
DOIs
StatePublished - 1 Jan 2014
Event29th Annual ACM Symposium on Applied Computing, SAC 2014 - Gyeongju, Korea, Republic of
Duration: 24 Mar 201428 Mar 2014

Publication series

NameProceedings of the ACM Symposium on Applied Computing

Conference

Conference29th Annual ACM Symposium on Applied Computing, SAC 2014
CountryKorea, Republic of
CityGyeongju
Period24/03/1428/03/14

Keywords

  • Flash Storage
  • FTL
  • SSD

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  • Cite this

    Chang, L-P., Huang, S. M., & Li, W. P. (2014). Optimizing FTL mapping cache for random-write workloads using adaptive block partitioning. In Proceedings of the 29th Annual ACM Symposium on Applied Computing, SAC 2014 (pp. 1504-1510). (Proceedings of the ACM Symposium on Applied Computing). Association for Computing Machinery. https://doi.org/10.1145/2554850.2554939