OSSD: Object-based Solid State Drive. Jin-Soo Kim Computer Systems Laboratory Sungkyunkwan University

Transcription

1 OSSD: Object-based Solid State Drive Jin-Soo Kim Computer Systems Laboratory Sungkyunkwan University

2 OSSD S S D + O S D O S S D NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim (jinsookim@skku.edu) 2

3 Motivation

4 Storage Interface Evolution 1980, Seagate ST , SCSI 1994, ATA Logical block addressing Dumb Integrated controller More intelligence? NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 4

5 Graphics Interface Analogy Setpoint (x, y); Raster graphics Drawline (x1, x2, y1, y2); Drawtext (x, y, Hello ); Vector graphics Polygons, Lighting, Z-buffering, Texture mapping, Alpha blending, OpenGL Direct3D NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 5

6 Interfaces for SSDs (1) Traditional block interface ATA/SCSI No block-level liveness information No high-level semantics on data Several unwritten contracts do not hold for SSDs Host File system Block device driver FTL NAND Flash SSD Block I/F Flash I/F NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 6

7 Interfaces for SSDs (2) Block interface with SSD extensions TRIM command What else? Host File system Not practical, sometimes impossible Block device driver FTL Block I/F + SSD-Specific I/F SSD NAND Flash Flash I/F NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim (jinsookim@skku.edu) 7

8 Interfaces for SSDs (3) Simplified SSD interface Interfaces specific to SSDs NVMHCI (Non-Volatile Memory Host Controller Interface) Mainly for PCIe-based SSDs Still works at the block level Host File system SSD driver FTL NAND Flash Simplified SSD I/F Flash I/F SSD NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 8

9 Interfaces for SSDs (4) Native flash interface READ PAGE, PROGRAM PAGE, ERASE BLOCK Used in many embedded systems Host handles everything, storage remains dumb and simple Host File system Flash device driver SSD FTL Flash File system NAND Flash Flash I/F NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 9

10 Interfaces for SSDs (5) Object interface More abstract interface Improved drive intelligence OSSD: Object-based Solid State Drive Host Object-based File System OSD driver OSD layer OSD I/F OSSD NAND Flash Flash I/F NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 10

11 OSD Object-based Storage Device Virtualizes physical storage as a pool of objects Offloads space management to storage devices Standardized as a subset of SCSI command set Block interface Object interface NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim (jinsookim@skku.edu) 11

12 Storage Model Host Application System Call Interface File System User Component Application System Call Interface File System User Component File System Storage Management OSD Interface Storage Device Sector/LBA Interface Block I/O Manager Physical Media Traditional OSD Storage Management Block I/O Manager Physical Media OSD NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 12

13 Linux Support for OSD Since Linux kernel Exofs + OSD initiator + iscsi transport VFS exofs ext3 udf bsg sd sr st osd_uld (osd.ko) osd_lld (libosd.ko) SCSI core (scsi_mod.ko) iscsi initiator SCSI initiator SCSI/ SATA SCSI SATA NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim (jinsookim@skku.edu) 13

14 OSSD Benefits (1) Simplified host file system No need for SSD-specific parameter tuning File-to-object mapping & access control More efficient management of flash storage Block-level liveness Metadata separation Object-aware storage management NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 14

15 OSSD Benefits (2) Application-aware storage management QoS requirements via attributes Application hints Storage virtualization Dynamic storage pool Multi-tier storage architecture with DRAM, PCM, SLC NAND, MLC NAND, and HDD NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 15

16 Prototype Implementation

17 Overall Architecture Host VFS Object -based File System Object-aware I/O Scheduler OSSD Initiator OSD Interface OSSD Target OSSD Firmware Object Management Layer (OML) Flash Management Layer (FML) Flash Abstraction Layer (FAL) NAND Flash NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 17

18 Host VFS OFS Prototype Architecture OID-Context Hash I/O OAQ Context oid =46 Priority Queue 46 7 C W Q n Q 1 OAQ OSSD Firmware OML FML FAL SCSI Subsystem libata READ/ WRITE / ERASE RawSSD NAND Flash SATA-2 OML FML oid =7 LRU Attribute Mapping 7 W 16:8 Q 0 Object I /O instances OID- Descriptor Index oid =7 oid = Object Descriptor Allocation Bitmap NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim (jinsookim@skku.edu) 18

19 Legacy Stack Host VFS EXT4 I/O Scheduler (CFQ) sftl FAL SCSI Subsystem libata READ/WRITE /ERASE RawSSD NAND Flash SATA-2 NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 19

20 RawSSD Native NAND I/O interface over SATA-2 16 chips * 8 dies/chip * 2GB/die = 256GB 8 channels (2 channels logically combined) 16KB logical page, 8MB logical block Two dies with two-plane operation Page-wise channel-level striping Asynchronous writes with DRAM buffer NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim (jinsookim@skku.edu) 20

21 Base Performance NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 21

22 Multi-threaded writes NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 22

23 Prioritized Reads HDV 1080i Requirement = 3.2MB/s) NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 23

24 Prioritized Writes NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 24

25 The OpenSSD Project

26 NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 26

27 Why OpenSSD? No more simulations Broaden research horizon Train people Share expertise Initiated with Prof. Sang-Won Lee (SKKU) and Indilinx NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 27

28 Jasmine OpenSSD Platform Indilinx Barefoot controller NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim 28

29 Jasmine Firmware Firmware released on April 7, 2011 The latest version: (April 15, 2011) Three sample FTLs Tutorial FTL (By Indilinx) Greedy FTL (By VLDB SKKU) Dummy FTL (By Indilinx) Toolchains ARM RVDS Codesourcery G++ lite edition NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim (jinsookim@skku.edu) 29

30 Participants 30 sets shipped to 9 institutions (15 labs) Sungkyunkwan U., Hanyang U., Ajou U., Hongik U., Korea U., Kwangwoon U., POSTECH, Soongsil U., U of Seoul 1 set shipped abroad We plan to have a workshop in May. NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim (jinsookim@skku.edu) 30

31 Jasmine Resources FAQs Board schematics Technical Reference Manual FTL Developer s Guide Barefoot Controller Technical Reference Contributions from community Developer Information (by Jeremy Brock) NVRAMOS 2011, Cheju Island, Korea, April 18 20, Jin-Soo Kim (jinsookim@skku.edu) 31

32 Thank You!