International Business Machines Corporation

Netapp, Inc.

Network Appliance, Inc.

Candera, Inc.

Chan Y Ng

Tuan Anh Nguyen

Rahim Ibrahim

Nghiep Tran

Kumar Gajjar

James C Chen

Richard Meyer

Glenn Yu

John Richard Paveza

Vernon John Legvold

Lloyd R Shipman, Jr

Ranjit Ghate

Thao Bich Bui

William G Sherman, Ii

Gen-Hwa Chiang

Carol Santich Michod

Julia Liu

Ashish Shah

David T Wang

Brent Cameron Beardsley

Jaishankar Moothedath Menon

Joseph S Hyde, Ii

Norman Ken Ouchi

Andrey Gusev

Gary Eugene Morain

Joe-Ming Cheng

James Cihla

Jeffrey R Steffan

Joel H Cord

Tram Thi Nguyen

Wellington C Yu

Steven Richard Van Gundy

Lawrence John Garibay

Robert Bruce Brodie

Charles Richard Lanzi

Andre Gusev

Christ J Xydes

Philip K Chai

The present invention provides a mechanism for fast routing of data in a Storage Area Network. A protocol interface module (PIM) interfaces with outside networks and the storage devices, such as over fiber channel (FC). The PIM encapsulates received data into a streaming protocol, enabling storage processors to direct data to/from the appropriate physical disk in a similar manner to the directing of network messages over the Internet or other network.

Method and apparatus for transferring information between different streaming protocols at wire speed

A storage virtualization controller for transferring data between a host and a storage device at a wire-speed data transfer rate. A downstream processing element adapted for connection to the storage device is configurable coupled to an upstream processing element adapted for connection to the host. A central processing element coupled to the upstream processing element grants permission to the upstream processing element to transfer the data at the wire-speed rate without further involvement by the central processing element.

High-speed data transfer in a storage virtualization controller

A method and apparatus for collecting information from ports on a storage network and performing flow control is provided. The data collection method and apparatus includes, identifying a data type transported on the storage network, selecting a port-storage identifier to measure the data type transported across the storage network, monitoring the port-storage identifier on the storage network for the data type, and enumerating occurrences of the data type associated with the port-storage identifier while monitoring the port-storage identifier and the data type. The flow-control operation receives information on a data type passing through the storage network according to a port-storage identifier, compares a threshold with the data type passing through the storage network according to a port-storage identifier, determines when the threshold associated with the data type has been exceeded in consideration of the information received, queues in response to the determination the data type scheduled to pass through one or more ports and storage devices identified according to the port-storage identifier on the storage network.

Method and apparatus for network storage flow control

Failover processing in storage server system utilizes policies for managing fault tolerance (FT) and high availability (HA) configurations. The approach encapsulates the knowledge of failover recovery between components within a storage server and between storage server systems. This knowledge includes information about what components are participating in a Failover Set, how they are configured for failover, what is the Fail-Stop policy, and what are the steps to perform when 'failing-over' a component.

Failover processing in a storage system

A storage virtualization system for accessing at least one storage device for a virtual logical unit (VLUN) from at least one host. The system includes at least one upstream processing element (UPE) which is adapted for coupling to a corresponding host server. The system is further adapted for coupling to at least one storage device. The controller also includes a primary central processing element (CPE) that can be configurably coupled to the UPEs. The primary CPE permits data transfer to occur between a host and a storage device via the corresponding UPE. The controller further includes a backup CPE that can be configurably coupled to the UPEs. The backup CPE is configurable to permit the data transfer when the primary CPE becomes unavailable.

Compensating for unavailability in a storage virtualization system

Detecting unavailability of primary central processing element, each backup central processing element associated with a group of virtual logic units and quiescing I/O operations of the primary central processing element in a storage virtualization system

A method and apparatus in a distributed processing environment for tracing events includes receiving a request to trace an event on a local processor, acquiring a sequence identifier associated with the local processor that associates the event with a chronological sequence of events on the local processor, storing the sequence identifier and information about the event in a local event trace associated with the local processor, providing the sequence identifer and information about the event to a remote processor for storage in a remote event trace. Consolidating the event traces from multiple processors into a single chronological event trace includes accessing a local event trace having one or more local trace events associated with the local processor, identifying a trace event entry having a local sequence identifier and referencing a remote processor, accessing a remote event trace associated with the remote processor and having a remote trace event entry matching the local sequence identifier, comparing the remote trace event entry with the local sequence identifier and one or more local trace events in the local event trace, and inserting the remote trace event entry into the local event trace based upon the comparison.

Tracing method and apparatus for distributed environments

A Virtual Storage Server is provided for transferring data between a source storage device and one or more destination storage devices. A write command is issued to the one or more destinations for an amount of data. In response, one or more Transfer Ready Responses are returned indicating the amount of data the destinations are prepared to receive. The Virtual Storage Server then sends a read command to the source for an amount of data based on the amounts of data in the Transfer Ready Responses. The data is then transferred from the source storage device through the Virtual Storage Server to the one or more destination storage devices. Because data is transferred only in amounts that the destination is ready to receive, the Virtual Storage Server does not need a large buffer, and can basically send data received at wire speed. This process continues until the amount of data in the write command is transferred to the one or more destination storage devices.

Data mover mechanism to achieve SAN RAID at wire speed

A staging method and means for both device read and update write operations in which messages and commands between a storage subsystem and a fixed-block formatted RAID array emulating a variable-length record (CKD) formatted device for both read and write operations are evaluated to ascertain whether the record addressing was random and truly in record mode. If they are in that mode, then partial track staging by the RAID array control from the fixed-block formatted HDDs to a subsystem cache or the like would reduce device contention by reading and staging less than full track.

Method and means for reducing device contention by random accessing and partial track staging of records according to a first DASD format but device mapped according to a second DASD format

Method and means for reducing device contention by random accessing and

A method and means within a hierarchical, demand/response DASD subsystem of the passive fault management type in which, upon the occurrence of fault, error, or erasure, a long device busy signal of finite duration is provided to a host CPU. Any DASD storage device subject to the anomaly is isolated from any host inquiry during this interval. These measures permit retry or other recovery procedures to be implemented transparent to the host and the executing application. This avoids premature declarations of faults, errors, or erasures and consequent host application aborts and other catastrophic measures. If the detected anomaly is not resolved within the allotted time, then other data recovery procedures can be invoked including device reset, the status reported to the host, and the next request processed.

Method and means for utilizing device long busy response for resolving

The present invention provides a method and system for detecting corrupted data of a plurality of hard disk drives (HDDs) in a data storage subsystem. In this system a predetermined number of fixed blocks within each of the HDDs emulate a track of a first track format. The predetermined number of fixed blocks provide a logical track. The logical track of one of the plurality of HDDs is generated by the others of the plurality of HDDs. The plurality of logical tracks forming a plurality of track groups. In a first aspect the method and system comprises assigning each of the plurality of logical tracks an address translation (ADT) number, comparing each of the ADT numbers of the plurality of logical tracks to an expected value until a mismatch occurs in a logical track, and determining if other logical tracks in a same track group have accurate ADT numbers. The first aspect further includes reconstructing the logical track if the other tracks within the same track group have accurate ADT numbers. In a second aspect the method and system comprises determining each of the plurality of logical tracks is formatted in accordance with first track format, comparing each of the formats of the plurality of logical tracks to the expected format until a mismatch occurs in a logical track, and determining if other logical tracks in a same track group have accurate first track formats. The second aspect includes reconstructing the logical track if the other tracks within the same track group have accurate first formats.

Method and system for detection and reconstruction of corrupted data in

A system and method for changing the number of logical volumes in a drawer in a rack in a direct access storage device subsystem is disclosed. The method and system are able to change the number of logical volumes without disrupting access to the other logical volumes in the rack. Channel connection addresses, which are logical volume addresses as known by the CPUs, are freed by removing the old drawer and then are mused. If the new drawer has more logical volumes than the old drawer, the next unused channel connection addresses are used with the new drawer. In a subsystem having a storage controller for providing control for a plurality of direct access storage devices, the logical volumes are spread across multiple physical devices. The storage controller maintains configuration data for the entire subsystem in redundant, non-volatile storage locations reserved specifically for its use. Each logical volume address for the rack is set by the drawer location and the logical sequence of the volumes within the drawer. As drawers are installed, the control unit sequentially assigns the volume addresses for the control unit and the channel connection addresses for the CPUs.

Method and system for maintaining concurrent data access during device

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San Jose, CA, United States of America

Chan Y Ng