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An Empirical Study of File Systems on NVM

Date

May 30, 2015

Author

Priya Sehgal, Sourav Basu, Kiran Srinivasan, and Kaladhar Voruganti

31nd International Conference on Massive Storage Systems and Technology (MSST 2015) 

Emerging byte-addressable,non-volatile memory like phase-change memory, STT-MRAM, etc. brings persistent latencies within an order of magnitude of DRAM, thereby motivating their inclusion on the memory bus. According to some recent research on NVM,traditional file systems are ineffective and sub-optimal in accessing data from this low latency media. However, there exists no systematic performance study across myriad file systems and their various configurations validating this point. We evaluate the performance of various legacy Linux file systems under various real world workloads on non-volatile memory (NVM) simulated using ramdisk and compare it against NVM optimized file system ­- PMFS. Our results show that while the default file system configurations are mostly sub-optimal for NVM, these legacy file systems can be tuned using mount and format options to achieve performance that is comparable to NVM-aware file system such asPMFS. Our experiments show that the performance difference between PMFS and ext2/ext3 with execute-in-place (XIP) option is only around 5% in many workloads (TPCC and YCSB). Furthermore, based on the learnings from our performance study, we present few key file system features such as in-place update layout with XIP, and parallel metadata and data allocations, etc. that could be leveraged by file system designers to improve performance of both legacy and new file systems on NVM.

Resources

The definitive version of the paper can be found at:

 http://storageconference.us/2015/Papers/10.Sehgal.pdf

 Slides presented at conference can be found at:

 http://storageconference.us/2015/Presentations/10.Sehgal.pr.pdf