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Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
Exploiting Non-Volatile RAM to Enhance Flash File System ...
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Exploiting Non-Volatile RAM to Enhance Flash File System ...

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  • 1. Exploiting Non-Volatile RAM to Enhance Flash File System Performance EMSOFT ’07 2008. 2. 20 Speaker: Yunjung Yoo
  • 2. Introduction <ul><li>NVRAM(Non-volatile Random Access Memory): </li></ul><ul><ul><li>The next generation memory that retains both non-volatile storage and random access memory </li></ul></ul><ul><ul><li>PRAM (Phase-change RAM) </li></ul></ul><ul><ul><li>FeRAM (Ferroelectric RAM) </li></ul></ul><ul><ul><li>MRAM (Magnetroresistive RAM) </li></ul></ul><ul><li>MiNVFS (Metadata in Non-Volatile RAM File System) </li></ul><ul><ul><li>File system that puts all metadata of the file system in NVRAM as maintaining metadata safely, and stores all the file data in Flash memory </li></ul></ul>
  • 3. Introduction <ul><li>NVRAMs Advantages over Flash memory </li></ul><ul><ul><li>The access time is faster than flash memory (Write access) </li></ul></ul><ul><ul><li>Overwrite existing data </li></ul></ul><ul><ul><li>No erasure limitation </li></ul></ul>2005 년 2 월 전자통신경향분석 제 20 권 제 1 호
  • 4. Design of the MiNV File System Information for managing the NVRAM The current status of each of the blocks The hash table that links all existing Inode
  • 5. Metadata in MiNVFS
  • 6. NVRAM Space Requirement for MiNVFS 16KB 512B 28B 16B 3072B 140B 32 140B
  • 7. NVRAM Space Requirement for MiNVFS <ul><li>NVRAM Space Requirement Model </li></ul><ul><ul><li>Need to model the space used by data structures </li></ul></ul><ul><ul><li>(1) the amount of NVRAM required by MiNVFS </li></ul></ul><ul><ul><li>(2) the fixed space required by NVRAM_Manager, Superblock, and Inode_Table </li></ul></ul><ul><ul><li>(3) the space needed for the Inode structures </li></ul></ul><ul><ul><li>(4) the space needed for the File_Offset structures </li></ul></ul>
  • 8. NVRAM Space Requirement for MiNVFS KB Worst case Best case
  • 9. NVRAM Space Requirement for MiNVFS <ul><li>The NVRAM space requirement increases linearly as the flash memory capacity increases </li></ul><ul><li>MP3 : about 4MB </li></ul><ul><li>Photo : about 330KB </li></ul><ul><li>Both the “MP3 case” and “Photo case” are very similar to that of the “Best case” </li></ul>
  • 10. NVRAM Space Requirement for MiNVFS <ul><li>Case of 1%(10MB) </li></ul><ul><ul><li>For 4MB(MP3) </li></ul></ul><ul><ul><li>20,000 metadata </li></ul></ul><ul><ul><li>250 contents </li></ul></ul><ul><ul><li>15,667KB NVRAM </li></ul></ul><ul><ul><li>For 330KB(Photo) </li></ul></ul><ul><ul><li>20,000 metadata </li></ul></ul><ul><ul><li>3,000 contents </li></ul></ul><ul><ul><li>16,223KB NVRAM </li></ul></ul><ul><li>In common case </li></ul><ul><ul><li>A few hundreds of metadata </li></ul></ul><ul><ul><li>10~20MB for CE today </li></ul></ul>
  • 11. Performance Evaluation <ul><li>Experimental Setup </li></ul><ul><ul><li>Implemented in Linux 2.4.x </li></ul></ul><ul><ul><li>Including the file system formatting tool and all the basic fs ops </li></ul></ul><ul><ul><li>Motherboard : EZ-M28 </li></ul></ul><ul><ul><ul><li>Processor : S3C2800 (ARM920T) </li></ul></ul></ul><ul><ul><ul><li>32MB SDRAM </li></ul></ul></ul><ul><ul><ul><li>64MB NAND flash memory </li></ul></ul></ul><ul><ul><li>NVRAM Daughter board : 12MB FeRAM </li></ul></ul><ul><ul><ul><li>Accessed via memory mapped addressing </li></ul></ul></ul>
  • 12. Performance Evaluation <ul><li>Correctness of the Model </li></ul>
  • 13. Performance Evaluation <ul><li>Mount time : compared to YAFFS </li></ul><ul><ul><li>YAFFS : The mount time increases linearly with utilization </li></ul></ul>
  • 14. Performance Evaluation <ul><li>With synthetic workloads </li></ul><ul><ul><li>Sequentially creating files and then deleting the files (5 times) </li></ul></ul><ul><ul><li>No updates on the files </li></ul></ul><ul><ul><li>The files created are all of the same particular size for each experiment </li></ul></ul><ul><ul><li>For YAFFS, the # presented in the table is not exact </li></ul></ul>
  • 15. Performance Evaluation <ul><li>* The way YAFFS creates files : </li></ul><ul><ul><li>Create & Write the metadata for the file </li></ul></ul><ul><ul><li>Then, write out the file data </li></ul></ul><ul><ul><li>Finally, create and the write a newly updated metadata, and invalidate the old metadata </li></ul></ul>
  • 16. Performance Evaluation <ul><li>With realistic workloads : TFFS benchmark program </li></ul><ul><ul><li>The FAX workload : managing the relatively large files </li></ul></ul><ul><ul><li>The Mobile Phone workload : managing the small files </li></ul></ul><ul><ul><li>The Event Recorder workload : Creating records and updating </li></ul></ul>Especially efficient for small file size and for the frequently updated files 152% 559% 600%
  • 17. Summary <ul><li>Presented the design and implementation of the MiNVFS </li></ul><ul><li>Exploiting NVRAM to store all of metadata </li></ul><ul><li>Modeling the NVRAM space requirement </li></ul><ul><ul><li>The amount of NVRAM required is in the 10’s of megabytes </li></ul></ul><ul><li>Conduct a series of experiments on a real board </li></ul><ul><ul><li>Mount time is drastically reduced (No scanning) </li></ul></ul><ul><ul><li>Significantly improved execution time (compared to YAFFS) </li></ul></ul><ul><li>Future work </li></ul><ul><ul><li>The energy consumption by NVRAM </li></ul></ul><ul><ul><li>Wear-leveling in flash memory (simplified??) </li></ul></ul><ul><ul><li>Further optimization in the design and implementation </li></ul></ul>

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