1.
    发明专利
    未知

    公开(公告)号:DE69521101T2

    公开(公告)日:2001-10-18

    申请号:DE69521101

    申请日:1995-10-06

    Applicant: IBM

    Abstract: A system and method for recovering from failures in the disk access path of a clustered computing system. Each node of the clustered computing system is provided with proxy software for handling physical disk access requests from applications executing on the node and for directing the disk access requests to an appropriate server to which the disk is physically attached. The proxy software on each node maintains state information for all pending requests originating from that node. In response to detection of a failure along the disk access path, the proxy software on all of the nodes directs all further requests for disk access to a secondary node physically attached to the same disk.

    2.
    发明专利
    未知

    公开(公告)号:DE69521101D1

    公开(公告)日:2001-07-05

    申请号:DE69521101

    申请日:1995-10-06

    Applicant: IBM

    Abstract: A system and method for recovering from failures in the disk access path of a clustered computing system. Each node of the clustered computing system is provided with proxy software for handling physical disk access requests from applications executing on the node and for directing the disk access requests to an appropriate server to which the disk is physically attached. The proxy software on each node maintains state information for all pending requests originating from that node. In response to detection of a failure along the disk access path, the proxy software on all of the nodes directs all further requests for disk access to a secondary node physically attached to the same disk.

    Digital storage system and method having alternating deferred updating of mirrored storage disks

    公开(公告)号:SG42854A1

    公开(公告)日:1997-10-17

    申请号:SG1996000149

    申请日:1994-07-15

    Applicant: IBM

    Abstract: A fault-tolerant high performance mirrored disk subsystem is described which has an improved disk writing scheme that provides high throughput for random disk writes and at the same time guarantees high performance for disk reads. The subsystem also has an improved recovery mechanism which provides fast recovery in the event that one of the mirrored disks fails and during such recovery provides the same performance as during non-recovery periods. Data blocks or pages which are to be written to disk are temporarily accumulated and sorted (or scheduled) into an order (or schedule) which can be written to disk efficiently, which in a preferred embodiment is in accordance with the physical location on disk at which each such block will be written. This also generally corresponds to an order which is encountered by a write head during a physical scan of a disk. The disks of a mirrored pair are operated out of phase with each other, so that one will be in read mode while the other is in write mode. Updated blocks are written out to the disk that is in write mode in sorted order, while guaranteed read performance is provided by the other disk that is in read mode. When a batch of updates has been applied to one disk of a mirrored pair, the mirrored pair switch their modes, and the other disk is updated. Preferably the updates are kept in a non-volatile memory, which furthermore advantageously may be made fault-tolerant as well. During recovery a pair of spare alternating mirrored disks is introduced to which new updates are directed, while a background scan process copies data from the surviving disk to the new mirrored pair.

    4.
    发明专利
    未知

    公开(公告)号:BR9403306A

    公开(公告)日:1995-06-20

    申请号:BR9403306

    申请日:1994-08-22

    Applicant: IBM

    Abstract: A fault-tolerant high performance mirrored disk subsystem is described which has an improved disk writing scheme that provides high throughput for random disk writes and at the same time guarantees high performance for disk reads. The subsystem also has an improved recovery mechanism which provides fast recovery in the event that one of the mirrored disks fails and during such recovery provides the same performance as during non-recovery periods. Data blocks or pages which are to be written to disk are temporarily accumulated and sorted (or scheduled) into an order (or schedule) which can be written to disk efficiently, which in a preferred embodiment is in accordance with the physical location on disk at which each such block will be written. This also generally corresponds to an order which is encountered by a write head during a physical scan of a disk. The disks of a mirrored pair are operated out of phase with each other, so that one will be in read mode while the other is in write mode. Updated blocks are written out to the disk that is in write mode in sorted order, while guaranteed read performance is provided by the other disk that is in read mode. When a batch of updates has been applied to one disk of a mirrored pair, the mirrored pair switch their modes, and the other disk is updated. Preferably the updates are kept in a non-volatile memory, which furthermore advantageously may be made fault-tolerant as well. During recovery a pair of spare alternating mirrored disks is introduced to which new updates are directed, while a background scan process copies data from the surviving disk to the new mirrored pair.

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