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Scalable Multimedia Servers. Walid G. Aref Research Scientist Panasonic Information and Networking Technologies Laboratory (PINTL) Princeton, New Jersey Starting Fall ‘99: Associate Professor Department of Computer Sciences Purdue University. Characteristics of Multimedia Data.
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Scalable Multimedia Servers Walid G. ArefResearch ScientistPanasonic Information and Networking Technologies Laboratory (PINTL) Princeton, New Jersey Starting Fall ‘99: Associate ProfessorDepartment of Computer SciencesPurdue University
Characteristics of Multimedia Data • Large number of objects • Large object sizes • Very high dimensionality • Retrieval by content • similar by not exactly the same • Real-time constraints • Spatial and temporal dependencies • e.g., as in video data
Target Features of a Multimedia Server • Support for a variety of multimedia types and formats • Real-time guarantees • Scalable • Reliable
Client/Server Multimedia System • Centralized server • Uses the serverhost to perform allof file systemfunctions • Storage elementsbehind the server • Server becomesbottleneck withincreasing users Server High Speed Network
Scalability of a Multimedia Server • Scale up with increasing user pool • Should not involve centralized entity • Distribute work among participating entities • Provide real-timeliness
Autonomous Disk Autonomous Disk Disks Attached to Network Server High Speed Network High Speed Network
Architecture for Distributed Multimedia Server Autonomous Disks 1 2 3 4 5 N Configuration Manager High Speed Network User Setup
Storage Architecture of Autonomous Disk • Network-Attached Storage Device • NASD Processor Memory Controller Network Interface Card
Functionality of a NASD • Light-weightprocessingand scheduling • Disk request scheduling • Network transmission • Access security check • Protocol processing
Volume Organization Autonomous attribute disk • Volume with non-intersecting and homogeneous disks A D D A Autonomous data disk • Volume with non-intersecting and non-homogeneous disks D A D D D D D • Volume with intersecting and homogeneous/non-homogeneous disks A D D D D D D D A Higher capacity higher bandwidth disk
Design Issues • Multimedia data striping • Volume management • Free list management • Concurrency control issues • Directory management • Access Security issues
Scheduling of NASD Devices • Resources with conflicting requirements • Disk Scheduling • Network Scheduling • User Requests with Real-time Deadlines • User Priorities • Multi-dimensional scheduling problem
Reliability • Storage Level Fault Tolerance • Hardware RAID • Software mirroring • Network Level Fault Tolerance • Redundant network and interfaces
Processor Memory Network and Disk Scheduler Network Interface Card Storage Real-Timeliness • Admission control • Bandwidth Enforcer Application API Assurance of real-timeliness DFS kernel Admission Controller Bandwidth Enforcer Network Client Host Autonomous Disk
Multimedia Traffic Characterization • Video data • variable-bit rate (VBR) • Self-similarity • Long-range dependency • Effect of data striping • More appropriate bandwidth enforcement algorithms
Data Mining in Multimedia Databases • Large amounts of multimedia data • surveillance applications (video data) • remote sensing • patient monitoring (video & time sequence data) • Huge amounts of data • Hard for human to make use of it • Target: Automatically detect regular/irregular patterns/sequences • Needs large-scale multimedia infrastructure
Courses in Multimedia Databases • Fall ‘99: CS690D - Advanced Topics in Multimedia Databases • Design and prototyping of serverless distributed multimedia systems • Scheduling in network-attached storage devices • Data mining in video databases • Retrieval by content and multimedia indexing
Courses in Multimedia Databases • Spring ‘2000: CS541 - Advanced Database Systems • Disk scheduling with real-time contraints • Incremental and online data mining algorithms • Generalized indexes (GiST) and their applications in multimedia databases • Retrieval by content and multimedia indexing