# US 7,412,594 B2 · Method and apparatus for managing data access and storage of data located on multiple storage devices > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,412,594 B2 - Document ID: US7412594B2 - Status: Granted - Kind: B2 - Application number: 10/801,263 - Filed: 2004-03-15 - Published: 2004-09-09 - Granted: 2008-08-12 - Earliest claimed: 1999-01-15 - Assignees: Oracle International Corporation - Inventors: William Bridge - Web page: https://patentgrep.com/patent/US7412594B2 ## CPC - G06F 3/0611: {in relation to response time} - G06F 3/0656: {Data buffering arrangements} - G06F 3/0689: {Disk arrays, e.g. RAID, JBOD} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract An apparatus and method for accessing a data item from a storage system having a plurality of data storage devices are disclosed. I/O operation requests are submitted to multiple data storage devices for each data item to be accessed. The I/O operation requests are issued to copies of the data items that reside on a plurality of data storage devices. More I/O operation requests are submitted than the number of data items that are to be accessed, written, or updated. ## Claims ### Claim 1 A system for reading a data item, comprising: means for maintaining a plurality of copies of said data item on a plurality of data storage devices; means for receiving a read request for said data item; means for initiating at least two read operation requests to at least two of said plurality of data storage devices in response to receiving said read request; and means for identifying a first one of said at least two read operations requests as projecting to produce a fastest response time. ### Claim 2 (depends on 1) The system of claim 1, further comprising the means for canceling a second one of said at least two read operation requests. ### Claim 3 (depends on 1) The system of claim 1, further comprising means for ignoring a copy of said data item retrieved by a second one of said at least two read operation requests. ### Claim 4 (depends on 1) The system of claim 1, wherein the means for identifying a first one of said at least two read operation requests includes means for identifying said first one of said at least two read operation requests as having a first movement from one level of request queues to another. ### Claim 5 (depends on 1) The system of claim 1, wherein the means for identifying a first one of said at least two read operation requests includes means for identifying said first one of said at least two read operation requests as having a first retrieval of a copy of said data item from one of said plurality of data storage devices. ### Claim 6 (depends on 1) The system of claim 1, wherein the means for maintaining a plurality of copies of said data item includes means for mirroring said data item from a first one of said plurality of data storage devices to a second one of said plurality of data storage devices. ### Claim 7 (depends on 1) The system of claim 1, wherein the means for maintaining a plurality of copies of said data item includes means for maintaining said plurality of copies of said data item on a plurality of disk drives. ### Claim 8 A method of reading a data item from a database, comprising: maintaining a plurality of copies of said data item from said database on a plurality of data storage devices; receiving a read request for a predetermined number of copies of said data item; initiating read operation requests to a selected number of the data storage devices in response to the read request, the selected number exceeding the predetermined number. ### Claim 9 (depends on 8) The method of claim 8 in which the data item comprises a video or audio data item. ### Claim 10 (depends on 9) The method of claim 9 in which the video or audio data item is associated with a video or audio stream. ### Claim 11 (depends on 9) The method of claim 9 in which the video or audio data item is associated with a video or audio stream. ### Claim 12 (depends on 8) The method of claim 8, in which the act of maintaining a plurality of copies of said data item is performed at a granularity level smaller than an entire disk drive. ### Claim 13 (depends on 8) The method of claim 8, further comprising identifying a first set of said read operation requests that are projected to produce a fastest response time. ### Claim 14 (depends on 13) The method of claim 13, further comprising canceling a second set of said read operation requests. ### Claim 15 (depends on 13) The method of claim 13, further comprising ignoring a copy of said data item retrieved by a second set of said read operation requests. ### Claim 16 A system for reading a data item from a database, comprising: means for maintaining a plurality of copies of said data item from said database on a plurality of data storage devices; means for receiving a read request for a predetermined number of copies of said data item; means for initiating read operation requests to a selected number of the data storage devices in response to the read request, the selected number exceeding the predetermined number. ### Claim 17 A computer program product that includes a volatile or non-volatile medium readable by a processor, the medium having stored thereon a sequence of instructions which, when executed by said processor, causes said processor to execute a process of reading a data item from a database, the process comprising: maintaining a plurality of copies of said data item from said database on a plurality of data storage devices; receiving a read request for a predetermined number of copies of said data item; initiating read operation requests to a selected number of the data storage devices in response to the read request, the selected number exceeding the predetermined number. ### Claim 18 (depends on 17) The computer program product of claim 17 in which the data item comprises a video or audio data item. ### Claim 19 (depends on 18) The computer program product of claim 18 in which the video or audio data item is associated with a video or audio stream. ### Claim 20 (depends on 18) The computer program product of claim 18 in which the video or audio data item is associated with a video or audio stream. ### Claim 21 (depends on 17) The computer program product of claim 17, in which the act of maintaining a plurality of copies of said data item is performed at a granularity level smaller than an entire disk drive. ### Claim 22 (depends on 17) The computer program product of claim 17, further comprising identifying a first set of said read operation requests that are projected to produce a fastest response time. ### Claim 23 (depends on 22) The computer program product of claim 22, further comprising canceling a second set of said read operation requests. ### Claim 24 (depends on 22) The computer program product of claim 22, further comprising ignoring a copy of said data item retrieved by a second set of said read operation requests. ### Claim 25 (depends on 16) The system of claim 16 in which the data item comprises a video or audio data item. ### Claim 26 (depends on 25) The system of claim 25 in which the video or audio data item is associated with a video or audio stream. ### Claim 27 (depends on 25) The system of claim 25 in which the video or audio data item is associated with a video or audio stream. ### Claim 28 (depends on 16) The system of claim 16, in which the means for maintaining a plurality of copies of said data item is performed at a granularity level smaller than an entire disk drive. ### Claim 29 (depends on 16) The system of claim 16, further comprising a means for identifying a first set of said read operation requests that are projected to produce a fastest response time. ### Claim 30 (depends on 29) The system of claim 29, further comprising a means for canceling a second set of said read operation requests. ### Claim 31 (depends on 29) The system of claim 29, further comprising a means for ignoring a copy of said data item retrieved by a second set of said read operation requests.