Computer system and process for transferring multiple high bandwidth streams of data between multiple storage units and multiple applications in a scalable and reliable manner

• US 20040243763A1
• Filed: 07/01/2004
• Published: 12/02/2004
• Est. Priority Date: 12/24/1997
• Status: Active Grant

• Current Assignee: Avid Technology Incorporated
• Original Assignee: Avid Technology Incorporated
• Inventors: Rabinowitz, Stanlely, Peters, Eric C., Fasciano, Peter J., Jacobs, Herbert R.
• Granted Patent: US 7,111,115 B2
• Time in Patent Office: Days
• US Class Current: 711/114
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/1662 the resynchronized component or unit being a persistent storage device re-synchronization of failed mirror storage G06F11/2082; rebuild or reconstruction of parity RAID storage G06F11/1008
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: G06F 16/184 implemented as replicated file system
• CPC Class Codes: G06F 16/1844 Management specifically adapted to replicated file systems
• CPC Class Codes: G06F 16/70 of video data
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: H04L 65/612 for unicast
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1029 using data related to the state of servers by a load balancer
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H04L 67/51 Discovery or management thereof, e.g. service location protocol [SLP] or web services
• CPC Class Codes: H04N 21/2182 involving memory arrays, e.g. RAID disk arrays RAID arrays per se G06F3/0689; use of parity to protect data in RAID systems G06F11/1008
• CPC Class Codes: H04N 21/23103 using load balancing strategies, e.g. by placing or distributing content on different disks, different memories or different servers storage management G06F3/0604; allocation of resources considering the load in multiprogramming arrangements G06F9/505; techniques for rebalancing the load in a distributed system G06F9/5083; access to distributed or replicated servers, e.g. load balancing, in data networks H04L67/1001
• CPC Class Codes: H04N 21/23116 involving data replication, e.g. over plural servers synchronization of replicated data G06F11/1658; error detection or correction by means of data replication G06F11/2053; replication in distributed file systems G06F16/10; replication in distributed file systems G06F16/27; replication or mirroring of data in data networks H04L67/1095
• CPC Class Codes: H04N 21/2312 Data placement on disk arrays data placement in general G06F3/0604
• CPC Class Codes: H04N 21/2315 using interleaving
• CPC Class Codes: H04N 21/232 : Content retrieval operation locally within server, e.g. reading video streams from disk arrays storage management G06F3/0604; details of querying and searching of video data from a database G06F16/739
• CPC Class Codes: H04N 21/2393 : involving handling client requests scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04N 21/2396 : characterized by admission policies admission control, resource allocation in open networks H04L12/5692; arrangements for network security using user profiles for access control H04L63/102; access security in wireless networks H04W12/08
• CPC Class Codes: H04N 21/2405 : Monitoring of the internal components or processes of the server, e.g. server load allocation of resources in multiprogramming arrangements G06F9/50; performance measurement of computer activity G06F11/34
• CPC Class Codes: H04N 21/241 : Operating system [OS] processes, e.g. server setup
• CPC Class Codes: H04N 21/262 : Content or additional data distribution scheduling, e.g. sending additional data at off-peak times, updating software modules, calculating the carousel transmission frequency, delaying a video stream transmission, generating play-lists scheduling strategies for dispatcher in multiprogramming arrangements G06F9/4881; arrangements for scheduling broadcast services or broadcast-related services H04H60/06; flow control in packet networks H04L47/10; establishing a time schedule or organising the servicing of application requests H04L67/62
• CPC Class Codes: H04N 21/44004 : involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 21/442 : Monitoring of processes or resources, e.g. detecting the failure of a recording device, monitoring the downstream bandwidth, the number of times a movie has been viewed, the storage space available from the internal hard disk arrangements for monitoring broadcast services or broadcast-related services H04H60/29; arrangements for identifying or recognising characteristics with a direct linkage to broadcast information H04H60/35; monitoring of user activities for profile generation for accessing a video database G06F16/739; monitoring in wireless networks H04W24/00
• CPC Class Codes: H04N 21/47202 : for requesting content on demand, e.g. video on demand
• CPC Class Codes: H04N 21/8456 : by decomposing the content in the time domain, e.g. in time segments
• CPC Class Codes: H04N 7/17336 : Handling of requests in head-ends
• CPC Class Codes: Y10S 707/99953 : Recoverability
• CPC Class Codes: Y10S 707/99956 : File allocation

Abstract

Multiple applications request data from multiple storage units over a computer network. The data is divided into segments and each segment is distributed randomly on one of several storage units, independent of the storage units on which other segments of the media data are stored. At least one additional copy of each segment also is distributed randomly over the storage units, such that each segment is stored on at least two storage units. This random distribution of multiple copies of segments of data improves both scalability and reliability. When an application requests a selected segment of data, the request is processed by the storage unit with the shortest queue of requests. Random fluctuations in the load applied by multiple applications on multiple storage units are balanced nearly equally over all of the storage units. This combination of techniques results in a system which can transfer multiple, independent high-bandwidth streams of data in a scalable manner in both directions between multiple applications and multiple storage units.

Claims

1. A distributed data storage system for allowing one or more client systems to access data, comprising:

a plurality of independent storage units for storing the data;

wherein the data is stored on the plurality of storage units in files, wherein each file includes segments of data and redundancy information for each segment, wherein each segment has an identifier, and wherein the redundancy information for each segment includes at least one copy of the segment, and wherein, for each file, the segments and the redundancy information for each segment are distributed among the plurality of storage units;

wherein each storage unit comprises means for maintaining information associating the identifier of each segment stored on the storage unit with the location of each segment on the storage unit;

wherein the distributed data storage system includes means for maintaining information associating the identifier of each segment with indications of the storage units from the plurality of storage units on which each segment and the redundancy information for the segment is stored;

wherein the distributed data storage system includes means for identifying one of the storage units to be removed; and

wherein the distributed data storage system includes means, operative in response to an identification of one of the storage units to be removed, for redistributing data on the identified storage unit to other storage units, including

means for determining, for each segment of data stored on the identified storage unit, another storage unit on which the segment is stored;

means for sending, for each segment of data stored on the identified storage unit, a request to the other storage unit on which the segment is stored to send a copy of the segment to a different storage unit, wherein each request includes the identifier of the segment.

2. The distributed data storage system of claim 1, wherein each copy of each segment is assigned to one of the plurality of storage units according to a probability distribution defined as a function of relative specifications of the storage units.

3. A process for recovering data in a distributed data storage system comprising a plurality of storage units for storing the data, wherein copies of segments of the data stored on the storage units are randomly distributed among the plurality of storage units, the process being performed when failure of one of the storage units is detected, comprising the steps of:

identifying segments of which copies were stored on the failed storage unit;

identifying storage units on which another copy of the identified segments was stored; and

randomly distributing a copy of the identified copies among the plurality of storage units.

4. A process for combining streams of video data to produce composited video data for storing the composited video data in a distributed system comprising a plurality of storage units for storing video data, wherein copies of segments of the video data stored on the storage units are randomly distributed among the plurality of storage units, comprising the steps of:

reading the streams of video data from the plurality of storage units;

combining the streams of video data to produce the composited video data;

dividing the composited video data into segments; and

randomly distributing copies of the segments of the composited video data among the plurality of storage units.