International Business Machines Corporation

Timothy M Damron

Teerasit Tinnakul

Justin King

Lee Nee Helgeson

Michelle A Schlicht

James P Allen

Stephen M Tee

Leslie James Record

Michael Edward Lyons

An error mechanism provides stored error information to assist in determining the cause of failure of a storage device such as a hard disk drive. The error mechanism gathers information surrounding an error event from various software and hardware components in the system. An event command is sent to the storage device that includes the gathered information. The storage device stores the gathered information from the event command in a log on the storage device. After the storage device is removed from the system the error information in the log can be used to determine the cause of the failure. The event command may be standardized into an existing industry communication protocol or be vendor specific.

Reporting errors to a data storage device

A mechanism is provided for balancing I/O among available paths connected to a device. The mechanism partitions paths so a device can use all or only a subset of available paths to a device, depending on the load of I/O for other devices that are sharing the paths. The partitioning of paths is dynamic, readjusting as I/O loads change for the devices.

Dynamic path partitioning to multipath storage devices

An error detection mechanism is provided for detecting sequential and distributed errors in a device I/O stream. The sensitivity of the errors is user definable. The result of the error detection is fed back into the path management software, which may use the error information to decide whether a device path should be disabled. The error detection mechanism sets a time span for a time window and counts the number of errors that occur during the time window. Each time a time window ends with at least one error, the sequential error count and the distributed error count are incremented. However, if an I/O returns without an error, the sequential error count is cleared. If the sequential error count reaches a predetermined limit, the path is disabled. After a predetermined number of time windows, if the distributed error count reaches a predetermined limit, the path is disabled.

Method, apparatus, and program for detecting sequential and distributed path errors in MPIO

A system and method for a dual stage persistent reservation preemption protocol is presented. A first adapter registers with a shared device and obtains reservation ownership of the shared device. The first adapter sets an internal reservation owner flag to 'TRUE' in response to obtaining reservation ownership. The internal flag status is analyzed if the first adapter is de-registered from the shared device. When a second adapter preempts the first adapter to obtain reservation ownership, the first adapter loses its registration with the shared device. The first adapter receives an error message from the shared device in response to a request, and the first adapter checks its internal reservation owner flag status. If the first adapter's internal reservation owner flag status is 'TRUE', the first adapter re-registers with the shared device.

System and method for dual stage persistent reservation preemption protocol

A method and system are disclosed for managing multiple requests issued by a requester to a number of peripheral devices coupled to a peripheral bus within a data processing system. A request issued by the requestor which specifies a particular operation to be performed is transmitted to a selected peripheral device vice the peripheral bus. In response to performance of the particular operation by the selected peripheral device within a first predetermined time period, successful completion of the request is reported to the requestor. In response to a failure of the selected peripheral device to perform the particular operation within the first predetermined time period, access to the peripheral bus by the multiple requests is limited. Thereafter, in response to a failure of the selected peripheral device to perform the particular operation within a second predetermined time period, a request timeout error is reported to the requester. However, in response to performance of the particular operation by the selected peripheral device within the second predetermined time period, successful completion of the request is reported to the requester. Thus, utilizing the present invention, request timeout errors due to peripheral bus saturation are minimized.

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Austin, TX, United States of America

Timothy M Damron