Report ： Zhen Ming Wu 2008 IEEE 9th Grid Computing Conference

 Introduction  Virtual Distributed Storage System Architecture Metadata Storage machine ISCSI server Design Performance controller  Evaluation Read and write performance Performance control  Conclusion

Strong demand for disk storage Abundant yet idle resources on desktop Machines Various performance requirements for Storage Service Call

Correctly service clients’ requests. Appears as a virtual volume stores three types of metadata about the system

Only Storage machine According to SAN Architecture keeping the database updated

act as the interface point responsible for maintaining enforcing access-control security policies replication strategies ： RAID 1

Bandwidth control with the help of a feedback controller dynamically throttles K ： Time interval y(k) ： sensor records the bandwidth r ： reference bandwidth

e(k) = r – y(k) ： control input actuator will enforces a delay function : (u(k)) But a smaller error e(k+1) = r – y(k+1)

Proportional controller ： e(k) control gain ： Kp integral controller ： Ki control output at the time ： u (k −1)

ISCSI server install Windows Server 2003 and MySQL database Storage machine install Fedora 7 and kernel Intel Xeon 8x CPUs at 2.33 GHz 16 GB RAM 250 GB SATA hard drive Windows Server using kernel

Clients Windows XP P4 CPU at 2.4 GHz 512 MB RAM 100 Mb/s fast network Create a NTFS file system on a virtual volume of 50 GB Compare the performance of and Windows CIFS

Test Read and write performance from 1MB to 2GB

Client sequentially writes a 20 GB file Client sequentially reads a 20 GB file Two client reads and writes to random locations in a 2 GB file Total runtime is 1,800 seconds Divided into three regions of 600 seconds Time interval of ten seconds record writes reads

Utilizes distributed machines to create an extremely large storage pool to provide predictable storage services feedback control can automatically throttle

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