1. iSCSI-based Virtual Storage System for Mobile Devices
Hyotaek Lim
Dongseo University

2. Outline
1. Background 2. iSCSI Protocol 3. Implementation 4. Performance Evaluation 5. Conclusion

3. Background Mobile Devices Advent of Thin Client World
Popular
Problem: Limited power
Advent of Thin Client World
Ubiquitous computing
Demand of of multimedia contents
Problem: Limited storage of mobile devices
 Virtual storage system for mobile devices

4. Background: What is iSCSI ?
A network transport protocol for SCSI that operates on top of TCP
iSCSI encapsulates SCSI protocol to TCP/IP so that SCSI storage controllers can be attached to IP networks
SCSI Class Driver
(SCSI Initiator)
iSCSI Protocol
Services
SCSI Device
(SCSI Target)
SCSI CDB
iSCSI
Protocol
Layer
TCP/IP
Ethernet
Data link +
Physical
SCSI Layer
Application
in IP
Datagrams
Frame
SCSI Application
SCSI Interface
Interface
iSCSI Transport
TCP/IP Protocol
iSCSI session
Logical Unit
I/O Request
TCP
segments
iSCSI Protocol Description
What is iSCSI? iSCSI is a new protocol standard in development by both the IETF (Internet Engineering Task Force) and t10
The Internet Engineering Task Force (IETF) is a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet.
T10 is a Technical Committee of the National Committee on Information Technology Standards (NCITS, pronounced "insights"). NCITS is accredited by, and operates under rules that are approved by, the American National Standards Institute (ANSI). These rules are designed to insure that voluntary standards are developed by the consensus of industry groups. NCITS develops Information Processing System standards, while ANSI approves the process under which they are developed and publishes them. NCITS was formerly known as the X3 Committee.
iSCSI uses encapsulation to pass SCSI requests between IP hosts running the iSCSI driver and the SN 5420 Storage Router allowing block-level access via IP.

5. Standard SCSI SCSI Over Network
iSCSI Protocol
User space
Kernel space
Target Emulator
Initiator
User Application
File System
SCSI
SCSI HBA Driver
Disk
iSCSI Subsystem
Transport Network
Network Stack
iSCSI
Subsystem
Standard SCSI SCSI Over Network

6. Wireless iSCSI data flow

7. Implementation
PDA uses remote SCSI Disk as a local disk

8. Implementation
Mp3 play

9. Implementation
MPEG play

10. Performance Measurement
- Target side Initiator side -
parameter
value
CPU
Intel Xeon 2.80GHz Dual CPU
OS / Kernel
Redhat Linux Fedora Core1 /
SCSI Interface
Adaptec aic7899 Ultra160
Disk Model
COMPAQ BD072863B2
Disk capacity
73.4 GB
Rotational latency
2.99 msec
(10,025 rpm)
iSCSI Target Driver
UNH-iSCSI(ref15)
parameter
value
CPU
Intel StrongARM 206MHz OS
Linux Familiar Project
(handhelds.org)
Kernel ver.
linux rmk6-pxa1-hh30 (ARM Kernel)
PDA Model
COMPAQ iPAQ-h3850
Memory
32M NAND Flash
/ 32 MB SDRAM
NIC
IEEE b
Wireless Interface
iSCSI Initiator
UNH-iSCSI referenced Implementation

11. Measurement tool: Bonnie, tioBench
Performance Measurement configuration
NFS vs iSCSI
Measurement tool: Bonnie, tioBench
Virtual local disk

12. Results (Bonnie) File Size : 100 MB(Single I/O), Result : KB/s 421 438
Configuration
NFS
iSCSI
Sequential Read
(KB/s)
421
438
423
499
Sequential Write
537
589
546
616
Avg. Random
Seek time(ms)
325
32.4
389
33.9

13. Results ( tioBench : CPU utilization )
I/O Thread num: 2, Result : Utilization(%)

14. Results( tioBench : IO throughput )
I/O Thread num: 2, Result : Throughput (KB/s)

15. Results (tioBench : Avg. Latency )
I/O Thread num: 2, Result : Latency (msec)

16. Conclusions conclusions Ongoing works
Implementation of iscsi-based virtual storage system for mobile devices
Performance evaluation
Ongoing works
adjustment our result to IPv6 networks
development of various applications based on our result
Caching techniques in our result

17. - iSCSI를 이용한 임베디드 장치의 활용 분야 -
                                                                                                                                                     
- iSCSI를 이용한 임베디드 장치의 활용 분야 -