
US Patent No: 6,006,342
Number of patents in Portfolio can not be more than 2000
Failover and failback system for a direct access storage device
Stats
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Dec 21, 1999
Issued date -
Dec 11, 1997
filing date -
08/988,887
serial no -
In Force
status
Importance
Abstract
Disclosed is a system for handling failures in a storage controller interfacing between a plurality of host systems and direct access storage devices (DASDs). The storage controller directs data from the host systems through a first and second data paths in the storage controller to a DASD. A first processor, first non-volatile memory unit (NVS), and a first cache are associated with the first data path and a second processor, a second NVS, and a second cache are associated with the second data path. A bridge provides communication between the first processor and the second NVS and the second processor and the first NVS. During normal operations prior to a failure in the storage controller, data directed to the first data path is written in the first cache and communicated with the first processor to the second NVS via the bridge for storage in the second NVS. Data directed to the second data path is written in the second cache and communicated with the second processor to the first NVS via the bridge for storage in the first NVS. A point of failure within at least one of the first processor, first cache, and first NVS is handled by routing the data directed to the first data path to the second processor and writing the routed data to the second cache and the second NVS. Upon repairing the point of failure, the data directed to the first data path is rerouted to the first processor, wherein the rerouted data is written in the first cache and communicated with the first processor to the second NVS via the bridge for storage therein.
First Claim
Related Publications
International Classification(s)
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Cited Art
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