International Business Machines Corporation

Globalfoundries Inc.

Stephen M Tee

James P Allen

Teerasit Tinnakul

John Leslie Neemidge

Timothy M Damron

Nicholas S Ham

James Anthony Pafumi

Chris Alan Schwendiman

Gary Steven Domrow

Bhyrav M Mutnury

Carol Santich Mellgren

Lance Warren Russell

Robert Edward Galbraith

Eric Philip Fried

Rajeev Kumar Mishra

Rick A Weckwerth

Sanket Rathi

Kiran Kumar Anumalasetty

Jared Michael Minch

Sudhir Maddali

Jacob Jason Rosales

Robert G Kovacs

Rodolfo Lopez

William J Maitland, Jr

James Britt Partridge

Stephen J Tovcimak

Dennis Carl Mairet

Jeffrey Michael Barnes

Nishant B Shah

Jayant Vitthalbhai Patel

Zhibao Hu

Systems and methods for replacing and testing a data storage device are disclosed. In disclosed embodiments, a system including a data storage array (DSA) including a plurality of data storage devices (DSDs) in an enclosure. The system further includes an I/O server coupling the DSA to a client node and configured to provide data access between the client node and the DSA. The system further includes a management server coupled to the DSA, configured to detect a failed DSD in the DSA, detect a replacement DSD in the enclosure that replaces the failed DSD, and add the replacement DSD to a logical path of the DSA. The management server is further configured to display an indication of a state of the DSA based on the comparing.

Servicing data storage devices in a data storage array

A method, system and computer program product are provided for implementing enhanced data caching and takeover of non-owned storage devices in a computer system. Each of a first controller and a second controller has a cache memory. During normal run-time, each storage device controller validates cached write data after it is written to its cache memory by reading the write data from its cache memory. If any error is detected on the read, then unit check failed storage device controller, which results in a reset of the failed storage device controller. When a storage device controller detects its dual partner controller fails, the surviving storage device controller queues host read/write operations for its storage devices already owned, and tests a cache mirrored copy from its cache memory of the failed first storage device controller before takeover of the failed controller's storage devices.

Implementing enhanced data caching and takeover of non-owned storage devices in dual storage device controller configuration with data in write cache

Techniques for switching between mirrored volumes are described. A system may comprise a multi-path device driver and a processor device, in communication with the multi-path device driver, operable in the computing storage environment. The processor device creates a copy relation identification (ID) between mirrored volumes for using the copy relation ID in conjunction with a multi-path device driver for switching input/output (I/O) for applications between a first path to a second path between the mirrored volumes.

Switching between mirrored volumes

A unique device name is assigned to each of a plurality of shared storage devices in a cluster configuration database defining membership of nodes in a cluster. A particular node among the nodes defined by the cluster configuration database as a member of the cluster searches the cluster configuration database for a device identifier matching a device identifier of a shared storage device hosted by the particular node. In response to finding a matching device identifier in the cluster configuration database, the particular node renames, in a local configuration maintained at the particular node, a storage device associated with the matching device identifier with the unique name assigned to that storage device in the cluster configuration database.

Propagation of unique device names in a cluster system

The present invention provides a computer implemented method and apparatus to revising logical unit ownership in a host. A host receives an error message from a storage subsystem having at least two storage controllers and at least one logical unit coupled to at least one of the storage controllers. The host suspends I/O from the host to the storage subsystem. The host transmits a verification of logical unit ownership query to the storage subsystem. The host determines that ownership between a host and a logical unit on the at least one of the storage controllers has changed from a mapping table of the host. Responsive to a determination that ownership has changed, the host updates ownership in a mapping table of the host to reflect the ownership between the host and the logical unit. The host resumes I/O from the host to the storage subsystem, wherein the host routinely exchanges I/O with the storage subsystem.

Stabilization of host to storage subsystem ownership

Disclosed is a computer implemented method and apparatus for queuing I/O requests to a pending queue. The I/O device driver sets a maximum ordered queue length for an I/O device driver coupled to a storage device then receives an I/O request from an application. The I/O device driver determines whether the pending queue is sorted and responds to a determination that the pending queue is sorted, determining if queued I/O requests exceed the maximum ordered queue length. Responding to a determination that the pending queue exceeds the maximum ordered queue length, the I/O device driver adds the I/O request based on a high pointer, and points the high pointer to the I/O request.

Transitions between ordered and ad hoc I/O request queueing

A method, system, and computer usable program product for an improved data storage device driver are provided in the illustrative embodiments. For managing an elevator queue, several requests are stored in the elevator queue. A determination is made whether the elevator queue is sorted. A number of requests in the elevator queue is determined if the elevator queue is unsorted. The unsorted elevator queue is monitored. Reaching a threshold condition in the unsorted elevator queue is detected. Sorting of the unsorted elevator queue is initiated. The requests may be I/O requests for a data storage device. The elevator queue may be sorted according to an ascending or descending order of data block addresses in the requests. The monitoring may monitor a remaining number of unsorted requests in the elevator queue as requests are removed from the elevator queue. The threshold condition may be associated with a threshold value.

Data storage device driver

In virtualized environments, storage may be managed dynamically due to the changing data storage requirements. In such environments, logical storage unit identifiers (LUN IDs) may be modified as a result of deleting an existing mapping between physical storage and a virtualization server and recreating the mapping. This can result in I/O request failure. Techniques for resolving errors resulting from LUN ID modifications can be time-intensive and labor-intensive and can disrupt a communication path between a host device and the physical storage. Functionality can be implemented to dynamically identify the LUN ID modifications, determine valid LUN IDs, and retransmit failed I/O requests. This can help minimize I/O request failures due to LUN ID modifications without disrupting the communication path between the host device and the physical storage.

Dynamically tracking virtual logical storage units

Embodiments that dynamically manage physical and virtual multipath I/O are contemplated. Various embodiments comprise one or more computing devices, such as one or more servers, having at least two HBAs. At least one of the HBAs may be associated with a virtual I/O server that employs the HBA to transfer data between a plurality of virtual clients and one or more storage devices of a storage area network. The embodiments may monitor the availability of the HBAs, such as monitoring the HBAs for a failure of the HBA or a device coupled to the HBA. Upon detecting the unavailability of one of the HBAs, the embodiments may switch, dynamically, from the I/O path associated with the unavailable HBA to the alternate HBA.

Dynamic physical and virtual multipath I/O

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

A method, computer program product, and a data processing system for maintaining object configuration data in a data processing system is provided. A first set of attribute entries is stored in a database. The first set of attribute entries is associated with a first object classification and a second object classification. A second set and a third set of attribute entries each including at least one attribute entry are stored in the database. The second set of attribute entries is associated with the first object classification, and the third set of attribute entries are associated with the second object classification. A first object of the first object classification is configured with the first set of attribute entries and the second set of attribute entries, and a second object of the second object classification is configured with the first set of attribute entries and the third set of attribute entries.

System and method for maintaining multiple devices with a single device identifier

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 mechanism is provided for monitoring I/O activity of each device and the total I/O activity for each adapter. When there is low I/O activity for the tape subsystem, the I/O for the disk subsystems may be spread across all available adapters and paths. When I/O activity for the tape subsystem increases, the I/O activity for the disk subsystems may be reduced on the adapter processing the tape I/O, but will continue across all other adapters. If the tape subsystem begins to report errors due to I/O starvation, the disk I/O activity may be adjusted until the errors stop.

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Marble Falls, TX, United States of America

Stephen M Tee