OMFS An Object-Oriented Multimedia File System for Cluster Streaming Server CHENG Bin, JIN Hai Cluster & Grid Computing Lab Huazhong University of Science & Technology HPCAsia, BeiJing, China, Dec. 2005

2 Outline Background Our Object-Oriented Method Improvement Schemes Performance Evaluation Conclusion

3 Background From Centralized Streaming Server to Cluster Streaming Server.

4 Background Existing cluster streaming servers I/O Bottleneck Poor Scalability Cluster File System Block-based File Operations Have to care about the media file format

5 Background Existing multimedia file systems Tiger Shark, PVFS  A general cluster file system HERMES, Symphony  focus on a QoS-aware disk scheduling algorithm, data placement, and cache policies. EXT3NS ( MM’05)  a local multimedia file system, not special for cluster streaming server

6 Background There are the following problems existing.  Most of them are used as a general cluster file system, such as PVFS  Not be specially designed for cluster streaming servers.  No uniform Interface

7 Background The features of media files  Various of file formats, such mp4, mov, avi  Different files have different objection organizations  Be consist of logical object units The features of cluster streaming server  Only perform reading operations  Seek objections according to timestamp.  Retrieve objects, such as meta object, data objects

8 Our goals An object-oriented multimedia file system specially designed for cluster streaming server  To provide an object-oriented method to fetch the media data  To present a single system image  To mask differences of multimedia file format  To separate the processing of multimedia files from cluster streaming servers  To enhance the performance of cluster streaming server.

9 Object Oriented Method Traditional processing method avi mov rm Cluster Streaming Server Parser_avi Parser_mov Parser_rm Block Parsing Object RTP Server RTSP Server consume a lot of CPU and memory resource, not efficient

10 Object Oriented Method avi mov rm Cluster Streaming Server Parser_avi Parser_mov Parser_rm RTP Server RTSP Server DB Meta Objects RTP Ojbects Uniform Interface Pre-processing Reading Apply the rule: Make the common case faster

11 Object-Oriented Framework

12 Optimization Schemes Bypassing kernel buffer Data Server NICDISK Data Server NICDISK 12 DataSend Command Kernel Module Bypassing

13 Optimization Schemes Creating time-based block indexing map WriteRead Data Object Key Frame Map

14 Performance Evaluation Simulation Setup  Our cluster streaming server has one Web Server, one Control Server, eight Data Servers, and one OMFS admin node. ---Two 1.4 GB AMD Opteron CPU ---2 GB Memory Mb/s Network Card ---avi, mp4, wmv Format  A multithreads simulator to generate requests, which accord with Poisson Distribution.

15 Performance Evaluation Metrics  Max Concurrent Stream Number  Max Throughput  CPU Overhead  Average VCR Waiting Time

16 Simulation Results Max Concurrent Stream Number about 12% improvement

17 Simulation Results Max Throughput

18 Simulation Results CPU Overhead

19 Simulation Results Delay of VCR Operation Streaming Server Type TotalTime (Sec.) AverageTime (Sec.) Darwin Streaming Server Our Cluster streaming Server with Time-based Indexing Map

20 Conclusion OMFS has the following features:  Simplify the design of cluster streaming server  Improve its performance  optimization schemes have great positive effect to the performance improvement of cluster streaming server.

21 That is all, Thank you!

22 Overview of OMFS

23 Inherited Tree of Objects

24 Uniform Interface OMFS_Write(int object_type, void * object_content) OMFS_Read(int object_type, void * object_content)