The emergence of Hybrid Shingled Magnetic Recording (H-SMR) allows dynamic conversion of the recording format between Conventional Magnetic Recording (CMR) and SMR on a single disk drive. H-SMR is promising for its ability to manage the performance/capacity trade-off on the disk platters and to adaptively support different application scenarios in large-scale storage systems. However, there is little research on how to efficiently manage data and space in such H-SMR drives.
In this paper, we present ZoneAlloy, an elastic data and space management scheme for H-SMR drives, to explore the benefit of using such drives. ZoneAlloy initially allocates CMR space for the application and then gradually converts the disk format from CMR to SMR to create more space for the application. ZoneAlloy controls the overhead of the format conversion on the application I/O with our quantized migration mechanism. When data is stored in an SMR area, ZoneAlloy reduces the SMR update overhead using H-Buffer and Zone-Swap. H-Buffer is a small host-controlled CMR space that absorbs the SMR updates and migrates those updates back to the SMR space in batches to bring down the SMR update cost. Zone-Swap dynamically swaps "hot" data from the SMR space to the CMR space to further alleviate the SMR update problem. Evaluation results based on MSR-Cambridge traces demonstrate that ZoneAlloy can reduce the average I/O latency and limit the performance degradation of the application I/O during format conversion.
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FluidSMR: Adaptive Management for Hybrid SMR Drives
Hybrid Shingled Magnetic Recording (H-SMR) drives are the most recently developed SMR drives, which allow dynamic conversion of the recording format between Conventional Magnetic Recording (CMR) and SMR on a single disk drive. We identify the unique opportunities of H-SMR drives to manage the tradeoffs between performance and capacity, including the possibility of adjusting the SMR area capacity based on storage usage and the flexibility of dynamic data swapping between the CMR area and SMR area. We design and implement FluidSMR, an adaptive management scheme for hybrid SMR Drives, to fully utilize H-SMR drives under different workloads and capacity usages. FluidSMR has a two-phase allocation scheme to support a growing usage of the H-SMR drive. The scheme can intelligently determine the sizes of the CMR and the SMR space in an H-SMR drive based on the dynamic changing of workloads. Moreover, FluidSMR uses a cache in the CMR region, managed by a proposed loop-back log policy, to reduce the overhead of updates to the SMR region. Evaluations using enterprise traces demonstrate that FluidSMR outperforms baseline schemes in various workloads by decreasing the average I/O latency and effectively reducing/controlling the performance impact of the format conversion between CMR and SMR.
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- Award ID(s):
- 1812537
- NSF-PAR ID:
- 10326845
- Date Published:
- Journal Name:
- ACM Transactions on Storage
- Volume:
- 17
- Issue:
- 4
- ISSN:
- 1553-3077
- Page Range / eLocation ID:
- 1 to 30
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1145/3465404
