Data Management and Layout for Shingled Magnetic Recording

作者：Amer Ahmed^*; Holliday JoAnne; Long Darrell D E; Miller Ethan L; Paris Jehan Francois; Schwarz Thomas

来源：IEEE Transactions on Magnetics, 2011, 47(10): 3691-3697.

DOI：10.1109/TMAG.2011.2157115

• Areal density
• data layout
• data management
• data storage systems
• memory
• shingled writing
• SMR
• two-dimensional magnetic recording (TDMR)

Ultimately the performance and success of a shingled write disk (SWD) will be determined by more than the physical hardware realized, but will depend on the data layouts employed, the workloads experienced, and the architecture of the overall system, including the level of interfaces provided by the devices to higher levels of system software. While we discuss several alternative layouts for use with SWD, we also discuss the dramatic implications of observed workloads. Example data access traces demonstrate the surprising stability of written device blocks, with a small fraction requiring multiple updates (the problematic operation for a shingled-write device). Specifically, we discuss how general purpose workloads can show that more than 93% of device blocks can remain unchanged over a day, and that for more specialized workloads less than 0.5% of a shingled-write disk's capacity would be needed to hold randomly updated blocks. We further demonstrate how different approaches to data layout can alternatively improve or reduce the performance of a shingled-write device in comparison to the performance of a traditional non-shingled device.

• 出版日期2011-10